Immunohistochemical Expression Research Articles

Maternal gastrointestinal nematode infection alters hippocampal neuroimmunity, promotes synaptic plasticity, and improves resistance to direct infection in offspring

The developing brain is vulnerable to maternal bacterial and viral infections which induce strong inflammatory responses in the mother that are mimicked in the offspring brain, resulting in irreversible neurodevelopmental defects, and associated cognitive and behavioural impairments. In contrast, infection during pregnancy and lactation with the immunoregulatory murine intestinal nematode, Heligmosomoides bakeri, upregulates expression of genes associated with long-term potentiation (LTP) of synaptic networks in the brain of neonatal uninfected offspring, and enhances spatial memory in uninfected juvenile offspring. As the hippocampus is involved in spatial navigation and sensitive to immune events during development, here we assessed hippocampal gene expression, LTP, and neuroimmunity in 3-week-old uninfected offspring born to H. bakeri infected mothers. Further, as maternal immunity shapes the developing immune system, we assessed the impact of maternal H. bakeri infection on the ability of offspring to resist direct infection. In response to maternal infection, we found an enhanced propensity to induce LTP at Schaffer collateral synapses, consistent with RNA-seq data indicating accelerated development of glutamatergic synapses in uninfected offspring, relative to those from uninfected mothers. Hippocampal RNA-seq analysis of offspring of infected mothers revealed increased expression of genes associated with neurogenesis, gliogenesis, and myelination. Furthermore, maternal infection improved resistance to direct infection of H. bakeri in offspring, correlated with transfer of parasite-specific IgG1 to their serum. Hippocampal immunohistochemistry and gene expression suggest Th2/Treg biased neuroimmunity in offspring, recapitulating peripheral immunoregulation of H. bakeri infected mothers. These findings indicate maternal H. bakeri infection during pregnancy and lactation alters peripheral and neural immunity in uninfected offspring, in a manner that accelerates neural maturation to promote hippocampal LTP, and upregulates the expression of genes associated with neurogenesis, gliogenesis, and myelination.

Survivin, β-catenin, and ki-67 immunohistochemical expression in canine perivascular wall tumors: Preliminary assessment of prognostic significance.

High survivin expression has been correlated with poor outcomes in several canine tumors but not in soft tissue tumors (STTs). Survivin is a target gene of the Wnt/β-catenin pathway, which is involved in human STT oncogenesis. Immunohistochemistry for survivin, β-catenin, and Ki-67 was performed on 41 canine perivascular wall tumors (cPWTs), and statistical associations of protein expression and histopathologic and clinical variables with clinical outcomes were investigated. Immunohistochemically, there was nuclear positivity (0.9%-12.2% of tumor cells) for survivin in 41/41 (100%), cytoplasmic positivity (0 to > 75% of tumor cells) for survivin in 31/41 (76%), nuclear positivity (2.9%-67.2% of tumor cells) for β-catenin in 24/41 (59%), and cytoplasmic positivity (0% to > 75% of tumor cells) for β-catenin in 23/41 (56%) of cPWTs. All tumors expressed nuclear Ki-67 (2.2%-23.5%). In univariate analysis and multivariate analysis (UA and MA, respectively), every 1% increase of nuclear survivin was associated with an increase of the instantaneous death risk by a factor of 1.15 [hazard ratio (HR) = 1.15; P = .007]. Higher nuclear survivin was associated with grade II/III neoplasms (P = .043). Expression of cytoplasmic survivin, nuclear and cytoplasmic β-catenin, and nuclear Ki-67 were not significantly associated with prognosis in UA nor MA. Tumor size was a significant prognostic factor for local recurrence in UA [subdistribution HR (SDHR) = 1.19; P = .02] and for reduced overall survival time in MA. According to UA and MA, a unitary increase of mitotic count was associated with an increase of the instantaneous death risk by a factor of 1.05 (HR = 1.05; P = .014). Nuclear survivin, mitotic count, and tumor size seem to be potential prognostic factors for cPWTs. In addition, survivin and β-catenin may represent promising therapeutic targets for cPWTs.

Exploring the Role of EZH2 and BCL2 in Demarcating Oral Verrucous Hyperplasia and Verrucous Carcinoma

Introduction Oral verrucous hyperplasia (OVH) and verrucous carcinoma (OVC) are precursors of oral squamous cell carcinoma exhibiting overlapping histopathological picture which warrants distinction. EZH2 is an epigenetic marker possessing multifaceted function in cellular proliferation, migration, and malignant transformation, whereas BCL2 is an integral part of the antiapoptotic mechanism regulating cellular homeostasis. Aim The aim was to distinguish OVH and OVC by analysis of immunohistochemical expression of EZH2 and BCL2. Material and Methods The study sample consisted of 79 formalin-fixed paraffin-embedded tissue sections of normal oral mucosa (10), OVH (10), oral OVC (27), and oral squamous cell carcinoma (32). Immunohistochemical analysis of EZH2 and BCL2 was done and labeling indices were calculated. Additionally, six histopathological parameters were assessed in OVH and OVC. Statistical analysis was done using Kruskal–Wallis test, Tukey honest significant difference test, and Spearman's correlation. Receiver operating characteristic curve was plotted and sensitivity, specificity, and cutoff score of each marker were calculated. Result and Discussion Labeling indices of EZH2 and BCL2 depicted a gradual incline from normal mucosa to oral squamous cell carcinoma. Significant difference of EZH2 and nonsignificant difference in BCL2 expression between OVH and OVC were noted. Out of the six histopathological parameters, keratin plugging, juxtaepithelial lymphocytic response, and frank endophytic growth yielded a significant difference. EZH2 serves as a superior marker than BCL2 to differentiate OVH and OVC. Juxtaepithelial lymphocytic response can also serve as a histopathological parameter in distinguishing OVH and OVC.

Role of MEK1 and DIAPH3 expression in colorectal adenoma-carcinoma sequence.

It is well established that most colorectal carcinomas arise from conventional adenomas through the adenoma-carcinoma sequence (ACS) model. mitogen-activated protein kinases (MAPKs) pathway has been reported as a crucial player in tumorigenesis. The MAPK signaling pathway is activated by different extracellular signals involving the "mitogen-activated/extracellular signal-regulated kinase 1 (MEK1)", and this induces the expression of genes involved in proliferation and cellular transformation. Diaphanous-related formin-3 (DIAPH3) acts as a potential metastasis regulator through inhibiting the cellular transition to amoeboid behavior in different cancer types. The aim of the study was to investigate the pattern of immunohistochemical expression of MEK1 and DIAPH3 in colorectal adenoma (CRA) and corresponding colorectal carcinoma (CRC) specimens. The immunohistochemical expression of DIAPH3 and MEK1 was examined in 43 cases of CRC and their associated adenomas using tissue microarray technique. MEK1 was overexpressed in 23 CRC cases (53.5%) and in 20 CRA cases (46.5%). DIAPH3 was overexpressed in 11 CRA cases (about 29%) which were significantly lower than CRC (22 cases; 58%) (P = 0.011). Both MEK1 and DIAPH3 overexpression were significantly correlated in CRC (P = 0.009) and CRA cases (P = 0.002). Tumors with MEK1 overexpression had a significantly higher tumor grade (P = 0.050) and perineural invasion (P = 0.017). Both MEK1 and DIAPH3 are overexpressed across colorectal ACS with strong correlation between them. This co- expression suggests a possible synergistic effect of MEK1 and DIAPH-3 in colorectal ACS. Further large-scale studies are required to investigate the potential functional aspects of MEK1 and DIAPH3 in ACS and their involvement in tumor initiation and the metastatic process.

A Preliminary Evaluation of the Prognostic Role of HER-2 and HER-3 Immunohistochemical Expression in Canine Melanomas.

Canine melanoma is a malignant and aggressive neoplasm showing clinical, histological, and molecular features similar to the human counterpart. In human medicine, epidermal growth factor receptors (EGFRs) have already been suggested as prognostic markers and potential therapeutic targets in cutaneous melanoma. The aim of this study was to evaluate the expression of HER-2 and HER-3 in canine melanomas by immunohistochemistry and correlate their expression to the clinicopathological parameters of the examined tumors. Thirty-seven canine melanoma samples were recruited. Data regarding signalment and clinical parameters were also collected. The population was composed of 18 cutaneous, 16 oral/mucosal, and three digital/foot pad melanomas. Histopathological investigations were carried out to analyze histological type, ulceration, and mitotic count. On each sample, immunohistochemistry was performed using an anti-Melan-A or anti-Melanoma antigen, i.e., anti-HER-2 and anti-HER-3 antibodies. HER-2 and HER-3 positivity were classified using already established scoring criteria and a statistical analysis was carried out. The results highlighted that HER-2 expression was observed in 48.6% of the samples and HER-3 expression in 18.9%. The highest HER 2 score (3+) was recorded in 16.2% of the samples, while the coexpression of the two receptors was detected in 13.5% of the samples. A statistically significant association (p < 0.05) was observed between the expression of HER-2 and HER-3 and the presence of ulceration in oromucosal tumors. This work confirms the expression of HER-2 and HER-3 in canine melanomas and suggests a putative association with negative prognostic parameters. Further studies are necessary to strengthen these data by increasing the samples size and combining pathological examinations with molecular biology in the investigation of EGFR family receptors.

Galectin-3 expression by thyroid neoplasms in a center in southwest Nigeria

Background: Galectin-3 (GAL-3), which is known to be expressed in certain normal tissues and is implicated in tumor progression and metastasis, serves as a valuable marker for distinguishing malignant thyroid lesions from benign thyroid lesions. This study aimed to assess the clinical and histopathological features of thyroid neoplasms at OAUTHC Ile Ife utilizing GAL-3 immunohistochemistry and to compare these findings with those of studies conducted in other regions of the world. Materials and Methods: Histology slides from 56 patients with thyroid neoplasms spanning a 20-year period were subjected to immunohistochemical staining with monoclonal antibodies against GAL-3. Evaluation was based on the 2022 World Health Organization Classification of Thyroid Neoplasms, categorizing marker expression as follows: 1+ (10–25% stained cells), 2+ (26–50% stained cells), 3+ (51–75% stained cells), and 4+ (&gt;75% stained cells). Negative staining indicated no staining, while localized staining (focal) represented &lt;50% of cells stained (1+ or 2+), and diffuse staining indicated &gt;50% of cells stained (3+ or 4+). Results: A total of 56 patients with neoplastic thyroid disease were studied, including 15 males and 41 females. Among the 16 benign neoplastic lesions, four (25.0%) exhibited focal GAL-3 expression, while 12 (75.0%) showed no expression. Among the forty malignant neoplastic lesions, five (12.5%) tested negative for the GAL-3 immunomarker, while 35 (87.5%) demonstrated positive expression to varying degrees. Among the positive malignant lesions, two (5.0%) displayed focal GAL-3 expression, while 33 (82.5%) exhibited diffuse staining of tumor cells. The diffuse and strong expression of GAL-3 was significantly greater in malignant thyroid neoplasms than in benign neoplasms (p&lt;0.05). The sensitivity and specificity of GAL-3 were 88% and 75%, respectively. Conclusion: Our findings align with the previous research indicating that diffuse and strong immunohistochemical expression of GAL-3 is indicative of thyroid gland malignancy. GAL-3 serves as a valuable tool in diagnosing thyroid neoplasms, particularly in cases where histomorphologic characteristics are inconclusive or unclear.

SGLT2 inhibitor as a potential therapeutic approach in hyperthyroidism-induced cardiopulmonary injury in rats.

Hyperthyroidism-induced cardiac disease is an evolving health, economic, and social problem affecting well-being. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2-I) have been proven to be cardio-protective when administered in cases of heart failure. This study intended to investigate the potential therapeutic effect of SGLT2-I on hyperthyroidism-related cardiopulmonary injury, targeting the possible underlying mechanisms. The impact of the SGLT2-I, dapagliflozin (DAPA), (1mg/kg/day, p.o) on LT4 (0.3mg/kg/day, i.p)-induced cardiopulmonary injury was investigated in rats. The body weight, ECG, and serum hormones were evaluated. Also, redox balance, DNA fragmentation, inflammatory cytokines, and PCR quantification in heart and lung tissues were employed to investigate the effect of DAPA in experimentally induced hyperthyroid rats along with histological and immunohistochemical examination. Coadministration of DAPA with LT4 effectively restored all serum biomarkers to nearly average levels, improved ECG findings, and reinstated the redox balance. Also, DAPA could improve DNA fragmentation, elevate mtTFA, and lessen TNF-α and IGF-1 gene expression in both organs of treated animals. Furthermore, DAPA markedly improved the necro-inflammatory and fibrotic cardiopulmonary histological alterations and reduced the tissue immunohistochemical expression of TNF-α and caspase-3. Although further clinical and deep molecular studies are required before transposing to humans, our study emphasized DAPA's potential to relieve hyperthyroidism-induced cardiopulmonary injury in rats through its antioxidant, anti-inflammatory, and anti-apoptotic effects, as well as via antagonizing the sympathetic over activity.

Abstract PO4-04-05: HER2 immunohistochemistry (IHC) expression in HER2-positive (HER2-pos) metastatic breast cancer (mBC): clinical and prognostic differences between IHC 2+ and IHC 3+ populations

Abstract Background: The exploration of heterogeneity in mBC has gained significant interest in optimizing therapeutic strategies. While the impact of differential HER2 IHC staining has been extensively studied in HER2-low neoplasms, limited data is available regarding IHC 2+ and IHC 3+ categories in HER2-pos mBC. The aim of our study is to compare, the clinical variables, metastatic patterns, and prognosis between patients classified as IHC 2+ and IHC 3+ in HER2-pos mBC. Methods: Pts with HER2 pos mBC, determined by HER2 IHC staining of 3+ or 2+ with amplification at the in situ hybridization assay, were selected from the GIM14 study database for analysis. Associations among variables were assessed by conducting logistic regression analyses. Additionally, prognostic factors for overall survival (OS) and time to treatment failure (TTF) were evaluated using both uni- and multi-variable Cox regression models. Results: A total of 766 HER2-pos mBC pts were included in the analysis. Among them, 302 (39%) had IHC score of 2+ and 464 (61%) had a IHC score of 3+. Central nervous system (CSN) metastases (mts) were observed in 68 (9%) pts (32% IHC 2+; 68% IHC 3+), lymph node (LN) mts in 330 (43%) pts (46% IHC 2+; 54% IHC 3+), lung (LU) mts in 182 (24%) pts (46% IHC 2+; 54% IHC 3+), liver (LI) mts in 227 (30%) pts (45% IHC 2+, 55% IHC 3+), skin (SK) mts in 68 (9%) pts (28% IHC 2+; 72% IHC 3+) and pleural (PL) mts in 40 (5%) pts (47% IHC 2+, 53% IHC 3+). In univariable (uni) analysis, IHC 3+ compared to IHC 2+ was significantly associated with SK mts (OR 1.76, P=0.043) and less likely to be associated with LI (OR 0.71, P=0.031), LU (OR 0.70, P =0.036), and LN (OR 0.63, P=0.002) mts. In multivariable (multi) analysis, LN mts maintained statistical significance (OR 0.62, P=0.004). In subgroup analysis, among IHC 3+ patients, factors associated with worse OS pts were neo Tx (HR 1.55, P=0.032), adjuvant radiotherapy (HR 1.34, P=0.042), neo ChT (HR 1.63, P=0.002), CNS mts (HR 1.98, P=0.002), and LI mts (HR 1.68, P&amp;lt; 0.0001). In multi analysis, CNS mts (HR 1.73, P=0.028) and LI mts (HR 1.47, P=0.017) remained prognostic for IHC 3+ subgroup. The only factor associated with worse OS in IHC 2+ pts was LI mts (HR 1.67, P=0.005). Multi analysis in the overall HER2-pos population identified neo chemotherapy (ChT) (HR 1.49, P=0.009), CNS mts (HR 1.53, P=0.003) and PL mts (HR 1.50, P=0.036) as negative prognostic factors for OS, while PL mts (HR 1.74, P=0.048) were associated with a shorter time to treatment failure (TTF). Conclusions: Our exploratory data revealed that HER2-pos mBC with a IHC score of 3+ is less likely to be associated with LN mts and with visceral mts. The site of mts has prognostic significance, as CNS mts are associated with worse OS in pts with an IHC score of 3+ pts, while LI mts are associated with worse OS in both IHC 2+ and 3+ subgroups. However, the IHC score itself (2+ or 3+) does not have independent prognostic value. The relationship between HER2 IHC staining and treatment outcomes requires further investigation to better understand its potential impact on clinical practice. Citation Format: Arianna Dri, Eva Blondeaux, Claudia Bighin, Simona Gasparro, Stefania Russo, Lorenzo Foffano, Palma Pugliese, Andrea Fontana, Enrico Cortesi, Antonella Ferzi, Ferdinando Riccardi, Valentina Sini, Luca Boni, Alessandra Fabi, Filippo Montemurro, Michelino De Laurentiis, Grazia Arpino, Lucia Del Mastro, Lorenzo Gerratana, Fabio Puglisi. HER2 immunohistochemistry (IHC) expression in HER2-positive (HER2-pos) metastatic breast cancer (mBC): clinical and prognostic differences between IHC 2+ and IHC 3+ populations [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-04-05.

Abstract PO4-02-09: Clinical outcomes of neoadjuvant chemotherapy in HER2-low early breast cancer

Abstract BACKGROUND: According to immunohistochemistry (IHC) expression of HER2 receptor, breast cancer (BC) can be classified as either IHC score 0, 1+, 2+ or 3+. Until recently, two distinct BC subtypes were recognized depending on the HER2 IHC expression and in situ hybridization (ISH) score: HER2 positive (IHC 3+ or IHC 2+ ISH-amplified) and HER2 negative (IHC 0, 1+ or 2+ ISH negative). More recently a new BC entity termed HER2-low was acknowledged, defined as either HER2 IHC 1+ or 2+ ISH-negative. Given that no treatment benefit was observed in HER2-low group of patients in the pivotal trastuzumab studies, many years had to pass before the discovery of antibody-drug conjugates such as trastuzumab deruxtecan, that led to a significant improvement in the clinical outcome of HER2-low BC, compared to standard therapy options. It is still debated whether HER2-low BC represents a distinct biological subtype. The aim of this study was to determine whether there is an impact of HER2-low status on the effect of neoadjuvant chemotherapy (NACT) and its primary indicator - the rate of the pathologic complete response (pCR). METHODS: A retrospective study of 363 BC cases who received NACT between January 2020 and December 2022 at University Hospital Centre Zagreb, Croatia, was conducted with prior Ethics Committee approval. Histopathological characteristics of tumours available from the hospital information system (BIS), including hormone receptor status (ER, PR), HER2 status and Ki-67 at the time of diagnosis and after neoadjuvant treatment, as well as pCR rates, were analysed. pCR rates were calculated for HER2-low and HER2 0 cases. Chi square test was used to analyse association between pCR rate and HER2 status. RESULTS: After exclusion of HER2 positive BC cases, as well as cases with missing data, a total of 215 patients were included in the analysis. Of those, 101 (47%) were HER2-low, and 114 (53%) were HER2 negative. The majority of patients (N=151, 70.2%) had luminal BC, while 64 (29.8%) patients had triple negative BC (TNBC). In the luminal group, 86 cases (57%) were HER2-low, and 65 (43%) were HER2 0. In the TNBC group, 15 cases (23.4%) were HER2-low and 49 (76.6%) were HER2 0. The rate of pCR among luminal subtypes was 6.2% for HER2-low tumours, and 15.4% for HER2 0 tumours (p=.051559), approaching statistical significance. In the TNBC group, the pCR rate for HER2-low group was 60%, compared to 40% in the HER2 0 group, trending towards, but not reaching statistical significance (p=.191564). CONCLUSION: A trend toward higher pCR rates after neoadjuvant chemotherapy was observed in the luminal HER2 0 group compared to HER2-low luminal BC, almost reaching statistical significance. Interestingly, in TNBC there was a trend towards higher pCR rates among the HER2-low group, although a small number of patients precludes any definitive conclusions. Further trials that include novel targeted therapies are needed, as that might lead to significant changes in therapeutic approach, as well as clinical outcome of HER2-low BC patients. Citation Format: Dora Gudelj, Katarina Čular, Lea Toula, Marija Križić, Marina Popović, Natalija Dedić Plavetić, Ana Kelečić, Gordana Ivanac, Majana Soče, Iva Kukal Gjergjaj, Tajana Silovski. Clinical outcomes of neoadjuvant chemotherapy in HER2-low early breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-02-09.

Abstract PS09-01: Individual patient data meta-analysis of clinical and translational biomarkers for prediction of pathological complete response (pCR) after de-escalated therapy in HER2+ breast cancer in four trials of the West German Study Group

Abstract Background Introduction of anti-HER2 therapies substantially improved outcomes for HER2-positive early breast cancer (HER2+ eBC). However, a considerable proportion of patients (pts) may still be overtreated with systemic chemotherapy (CTx) combinations. Establishing safe de-escalation strategies to avoid toxicities requires precise patient selection. Therefore, we set out to determine predictors for efficacy and survival in the unique setting of four de-escalation trials investigating short (12-week) neoadjuvant treatments (NAT) in HER2+ eBC. We investigated the prognostic ability of clinical and translational biomarkers for pCR to identify pts with the best prognosis after de-escalated systemic CTx-free NAT. Methods 756 pts who received de-escalated NAT were analyzed: trastuzumab + pertuzumab (T + P, n=92) and T + P + paclitaxel (pac, n=42) in ADAPT-HR-/HER2+ (NCT01817452); trastuzumab emtansine (T-DM1, n=118), T-DM1 + endocrine therapy (ET, n=125), and T + ET (n=129) in ADAPT-HR+/HER2+ (NCT01779206), T + P + pac (n=107) and T + P + ET (n=100) in TP-II (NCT03272477); and T + P + pembrolizumab (n=43) in Keyriched-1 (NCT03988036) in HER2-enriched (HER2-E) subtype by PAM50. The primary endpoint of each trial was pCR (ypT0/is ypN0). Survival was a secondary endpoint in all trials but Keyriched-1; survival data for TP-II are pending. Baseline gene expression was analyzed by BC360 assay; intrinsic molecular subtypes were determined using the PAM50 predictor. Stromal tumor infiltrating lymphocytes (sTILs) were evaluated at baseline and at week 3 of NAT. sTILs were categorized using a 30% threshold and the low cellularity category ( &amp;lt; 500 invasive tumor cells) at week 3. Prognostic markers for pCR were identified with univariate and multivariable logistic regression models with backstep algorithm excluding variables with p≥0.1; considered variables included age, sTILs (baseline, 3-weeks), cT, cN, grade, hormone receptor and HER2 status, intrinsic subtype, and standardized ERBB2 and ESR1 gene expression. These analyses were performed separately for NAT involving systemic CTx (i.e. containing pac, n=149) and systemic CTx-free NAT (n=607). Results Overall pCR rate was 39.1% (CTx: 66.4%; CTx-free: 32.5%). Multivariable analysis identified predictors of pCR after CTx-free NAT: low cellularity at week 3 (vs &amp;lt; 30% sTILs: OR 3.21, 95%CI 1.85-5.57), ERBB2 (OR 1.90, 95%CI 1.41-2.55), HER2 3+ (vs 1+/2+ and ISH+: OR 8.01, 95%CI 1.65-38.99), LumA/LumB/Basal subtype (vs HER2-E: OR 0.57, 95%CI 0.34-0.97), cT2 (vs 1: OR 0.54, 95%CI 0.33-0.89), and cN1-3 (vs 0, OR 0.46, 95%CI 0.27-0.78). In CTx-containing NAT, only ERBB2 (OR 2.08, 95%CI 1.28-3.40) and additionally ESR1 (OR 0.38, 95%CI 0.23-0.61) were prognostic for pCR. Updated analysis including expanded gene expression data from ADAPT-HR+/HER2+ and a prognostic score for pCR after CTx-free NAT developed using machine learning methods will be presented at the meeting. Conclusions This pooled analysis demonstrated a 66% pCR rate after a short (12-week) de-escalated NAT in HER2+ eBC. In one-third of patients (with mainly stage I cancer, higher HER2 expression by immunohistochemistry and gene expression analysis, and low cellularity at 3 weeks), pCR can be achieved without systemic CTx. Identified biomarkers could pave the way for developing new patient selection strategies to spare CTx-associated acute and late toxicities in a clinically meaningful number of patients. Citation Format: Monika Graeser, Oleg Gluz, Christine zu Eulenburg, Sherko Küemmel, Raquel von Schumann, Matthias Christgen, Rachel Wuerstlein, Enrico Pelz, Hans-Heinrich Kreipe, Peter Schmid, Marc Thill, Michael Braun, Jochem Potenberg, Claudia Schumacher, Joke Tio, Andreas Hartkopf, Marianne Just, Christian Schem, Kerstin Lüdtke-Heckenkamp, Eva-Maria Grischke, Felix Hilpert, Angela Kentsch, Ronald Kates, Ulrike Nitz, Nadia Harbeck. Individual patient data meta-analysis of clinical and translational biomarkers for prediction of pathological complete response (pCR) after de-escalated therapy in HER2+ breast cancer in four trials of the West German Study Group [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS09-01.

Abstract PO1-17-04: Influence of regulatory agency approval of trastuzumab-deruxtecan on the diagnosis of HER2-low status at a reference cancer center in Brazil

Abstract BACKGROUND HER-2 low status is defined by immunohistochemistry (IHC) expression for human epidermal growth factor receptor 2 (HER-2) 1+ or IHC 2+ without gene ERBB2 amplification. HER2-low breast cancers (BC) accounted for approximately 55% of all cases, and among hormone receptor positive (HR+) tumors it represents up to 60% of patients (pts), while 10-20% in triple negative tumors (TNBC). Trastuzumab-deruxtecan (T-dxd) has been FDA approved for HER-2 low breast cancer after Destiny-Breast 04 trial (DB04) demonstrated a robust overall survival benefit either in HR+ or TNBC heavily pre-treated pts. The Brazilian Health Regulatory Agency (ANVISA) has later approved T-dxd for HER-2 low BC. However, due to its dynamic nature and subjectivity, the definition of HER-2 low status still lacks better criteria. This study aims to evaluate whether HER-2 low status diagnosis was impacted according to the time of the diagnosis - before DB04 publication and after ANVISA drug approval - in a reference cancer center in Brazil. METHODS This retrospective study was conducted in a single institution in Sao Paulo, Brazil. Pts diagnosed with BC between October 1st 2021 to June 1st 2023 were classified in 2 groups according to the time of diagnosis. Group 1 (g.01) included those who were diagnosed between October 1st 2021 until DB04 publication in July 7th 2022; and Group 2 (g.02) included pts diagnosed after ANVISA T-dxd approval on October 31st, 2022 until June 1st 2023. All pathological analysis of the primary breast tumor was performed by 2 experienced breast pathologists. HER-2 IHQ Score was defined according to ASCO/CAP guideline 2018. The primary endpoint was to evaluate the proportion of patients who were defined as HER-2 low according to the time of diagnosis. Secondary endpoint consists in evaluate change in pathologists practice to distinguish IHC 1+ results from 0 after the definition of HER-2 low. To compare the categorical variables between the groups, the Chi-square test was used. P values below 0.05 were considered statistically significant. Statistical analyses were carried out with the R program (R Foundation, Vienna, Austria). RESULTS A total of 713 pts with diagnosis BC were included in the study, 401 (56%) in g.01 and 312 (44%) in g.02. Overall, before DB04 publication, the diagnosis HER “Negative-NOS” without subdivision in score 0 or 1 was found in 127 (31.7%), but only in 27 (8.7%) reports in g.02 (p=0.007-13). HER-2 low status was observed in 12.2% in g01 and in 33.3% of the pts in g.02 (p &amp;lt; 0.00001). Specifically, negative score 0 was found in 45.6% of pts in g.01 and 44.6% in g.02 (p= 0.014). A significant difference was also observed among pts with negative Score 1+ between groups (6.0% vs 21.2%, p=0.009-3), as shown in Table 1. No significant difference was seen in the frequency of HER2 score 2+ and score 3+ between g.01 and g.02. CONCLUSION The recent impact of a highly effective treatment derived from definition of HER-2 low BC led to a greater relevance in differentiating IHC 1+ from IHC 0, both considered HER negative by ASCO/CAP protocols. Distinguishing between HER2 0 and 1+ is subject to considerable interobserver variability , and the time of regulatory approval demonstrated a direct influence on the HER-low diagnosis. Table 1 Distribution of HER2 IHQ results in Group 1 and Group 2 Citation Format: Paula Martinez Vianna, Venancio Avancini Ferreira Alves, Pedro Exman. Influence of regulatory agency approval of trastuzumab-deruxtecan on the diagnosis of HER2-low status at a reference cancer center in Brazil [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-17-04.

Abstract PO2-25-11: Incidence of Breast Cancer in Louisiana Compared to the United States

Abstract Aside from skin cancer, breast cancer is the most common cancer in American women. More specifically, one in eight women will develop breast cancer during their lifetime. Breast cancer is classified into subtypes defined by immunohistochemistry (IHC) expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). ER+/PR+/HER2- tumors are the most common form of breast cancer and are typically associated with risk factors including older age, nulliparity, obesity following menopause, alcohol and tobacco use, sedentary lifestyle, and hormone therapy. ER-/PR-/HER2+ tumors comprise approximately 15-20% of breast cancers and are caused by overexpression of the HER2 gene. These tumors have similar risk factors to ER+/PR+/HER2- tumors, except for age. Women with HER2+ breast cancer are likely to be younger compared to ER+PR+/HER2-. Tumors lacking hormone receptors are classified as ER-/PR-/HER2-, otherwise known as triple-negative breast cancer (TNBC). TNBC represents 10%-20% of breast cancers and carries a poorer prognosis, shorter survival, and unresponsiveness to hormone therapy compared to other forms of breast cancer. TNBC has been associated with African American race, socioeconomically deprived population, younger age at diagnosis (most frequently in women ages 40-50), more advanced disease stage, higher grade, high mitotic indices, family history of breast cancer and BRCA1 mutations. The primary aim of this study is to compare incidence of ER+/PR+/HER2-, ER-/PR-/HER2+, and ER-/PR-/HER2- (TNBC) in Louisiana to the national population. The Louisiana Tumor Registry (LTR) was utilized to obtain state and national level data. The LTR is a participant of the National Cancer Institute’s Surveillance, Epidemiology and End Results Program, and the Centers for Disease Control and Prevention’s National Program of Cancer Registries. Our study evaluated women in Louisiana diagnosed with ER+/PR+/HER2-, ER-/PR-/HER2+, and ER-/PR-/HER2- from 2010-2019. The populations were subdivided by age at time of diagnosis. Data was subdivided into ages 0-49, and &amp;gt;50. Rates were calculated per 100,00 and age-adjusted to the 2000 United States Standard Population (19 age groups - Census P25-1130). A p-value of &amp;lt; 0.05 indicates a significantly different rate in Louisiana comparative to the United States (SEER). Our results are as follows. Unexpectedly, Louisiana has a significantly lower rate of ER+/PR+/HER2- cancer in women ages 0-49 and ages &amp;gt;50 compared to the United States. Based on epidemiological risk factors, Louisiana should have a much higher rate of ER+/PR+/HER2- comparative to the United States population. Louisiana has a significantly higher rate of ER-/PR-/HER2+ cancer in women ages &amp;gt;50 and ER-/PR-/HER2- (TNBC) in women ages 0-49 and ages &amp;gt;50 compared to the United States. These findings are discordant with traditional epidemiologic studies regarding breast cancer and require further investigation. Breast Cancer Incidence Rates1 by Age from 2010-2019 in Louisiana and the United States Table 1: Breast Cancer Incidence Rates in women ages 0-49 and ages &amp;gt;50 from 2010-2019 in Louisiana Compared to the United States. Citation Format: Avery Daily, Julie Cupp, Krystle Trosclair. Incidence of Breast Cancer in Louisiana Compared to the United States [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-25-11.

Pleural mesothelioma from fluoro-edenite exposure: PACAP and PAC1 receptor. A preliminary report.

Pleural mesothelioma is a devastating malignancy primarily associated with asbestos exposure. However, emerging evidence suggests that exposure to fluoro-edenite fibers, a naturally occurring mineral fiber, can also lead to the development of pleural mesothelioma. In this study, based on the hypothesis that pituitary adenylate cyclase-activating polypeptide (PACAP) and PACAP-preferring receptor (PAC1R) expressions could be dysregulated in pleural mesothelioma samples and that they could potentially act as diagnostic or prognostic biomarkers, we aimed to investigate the immunohistochemical expression of PACAP and PAC1R in pleural biopsies from patients with pleural mesothelioma exposed to fluoro-edenite fibers. A total of 12 patients were included in this study, and their biopsies were processed for immunohistochemical analysis to evaluate the expression of PACAP and its receptor. The study revealed a correlation between the overexpression of PACAP and PAC1R and shorter overall survival in patients with malignant mesothelioma. These findings suggest that PACAP and PAC1R expression levels could serve as potential prognostic biomarkers for malignant mesothelioma. Furthermore, the immunohistochemical analysis of PACAP and PAC1R may provide valuable information for clinicians to guide therapeutic decisions and identify patients with poorer prognosis.

Abstract PO3-03-05: Clinical outcomes in early-stage TNBC according to HER2-low status

Abstract Background: Clinical outcomes according to HER2 immunohistochemistry (IHC) in patients with early-stage HER2-negative breast cancer have differed across studies. For early-stage TNBC (eTNBC), less representation of this subtype in cohorts studied to date has limited interpretation of results. We sought to evaluate outcomes according to HER2 IHC in a multi-institutional cohort of patients (pts) with eTNBC who received neoadjuvant therapy (NAT). Methods: Pts diagnosed with stage I-III TNBC (including HR-low; ER and PR &amp;lt; 10%) who received NAT and underwent surgery between 1/1/16-6/30/19 were identified across three institutional prospective databases. HER2 was defined as low (1+ or 2+/ISH non-amplified) or HER2-0 according to local testing at diagnosis. Pathological complete response (pCR) was defined as no residual invasive disease in breast and axilla. Multivariable logistic regression was used to compare pCR rates (HER2-low vs HER2-0) adjusting for age at diagnosis, race, anatomic clinical stage, germline BRCA1/2 (gBRCA), histology, HR status and receipt of anthracycline and taxane NAT. Recurrence-free (RFS), distant recurrence-free (DRFS), and overall survival (OS) were estimated using the Kaplan-Meier method. Multivariable Cox proportional hazards model was used to estimate adjusted hazard ratios. Results: A total of 978 pts were identified of which 388 (39.7%) had HER2-low and 590 (60.3%) had HER2-0 tumors at diagnosis. Median age was 50.3 (range: 21.0-83.4) yrs. 174 (17.8%) pts had HR-low tumors. 142 (14.5%) pts had a known gBRCA mutation. 790 pts (80.8%) received anthracycline- and taxane NAT. No significant differences were observed in age, race, gBRCA, histology, HR status (low vs negative), clinical tumor size, or type of NAT between HER2-low and HER2-0 groups. Clinical nodal positivity was higher in HER2-low (55.2%) vs HER2-0 (46.6%), p=0.011. No significant difference in pCR was observed between HER2-low (32.0%) and HER2-0 (32.7%) groups, adjusted p=0.928. Among pts with residual disease (RD) post-NAT with HER2 IHC also available in the RD sample, 244/363 (67.2%) had concordant HER2 status. 70/225 (31.1%) of HER2-0 tumors at diagnosis had IHC expression post-NAT (66 HER2-low, 4 HER2-positive); 48/138 (34.8%) of HER2-low tumors at diagnosis were HER2-0 post-NAT. At a median follow-up of 3.1 yrs, RFS did not significantly differ between HER2-low vs HER2-0 pts with pCR (p=0.368) or in those with RD post-NAT (p=0.573). Similarly, DRFS did not differ according to HER2 category for pts with pCR (p=0.509) or RD (p=0.812), nor did OS for pts with pCR (p=0.514) or RD (p=0.285) (Table 1). Conclusion: In a large cohort of pts with eTNBC treated with NAT, HER2-low status was not associated with pCR or survival after adjusting for clinical factors. High rate of discordance in HER2 IHC between diagnostic and RD post-NAT was observed, highlighting the importance of repeat IHC testing in serial samples given the development of antibody drug conjugates for HER2-low breast cancer. Table 1. RFS, DRFS and OS by HER2 expression Citation Format: Ana Garrido-Castro, Danielle Brandes Zakon, Qingchun Jin, Michael Grimm, Akshara Singareeka Raghavendra, Melissa Hughes, Mathew Cherian, Julie Vincuilla, Tonia Parker, Paolo Tarantino, Elizabeth Mittendorf, Tari King, Vicente Valero, Debu Tripathy, Bhuvaneswari Ramaswamy, Sara Tolaney, Nabihah Tayob, Nancy Lin, Daniel Stover, Carlos Barcenas. Clinical outcomes in early-stage TNBC according to HER2-low status [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-03-05.

Does Autophagy have a Role in the Pathogenesis of Pediatric Hepatic Steatosis?

this study aimed to evaluate the immunohistochemical expression of Beclin1 and LC3A in pediatric hepatic tissues with steatosis and to correlate their expression with clinicopathological parameters. this study included 81 Egyptian pediatric patients with hepatic steatosis and 21 pediatric cases without hepatic steatosis. All specimens were stained by Beclin1 and LC3A antibodies. According to final diagnosis obtained from Pediatric Hepatology department, patients were divided into two groups: chronic liver disease (CLD) group that included 45 cases and inborn error of metabolism (IEM) group that included 36 cases. higher beclin1 expression was significantly correlated with higher stages of fibrosis and distorted liver architecture in CLD group, (P=0.043) for both. The control group showed higher positivity, percentage, as well as the median values of the H score of LC3A expression than did the CLD group or the IEM group (P=0.055, 0.001, and 0.008, respectively). Higher positivity of LC3A was significantly associated with higher stages of fibrosis and distorted liver architecture in the studied IEM group (P=0.021) for both. Varying intensity grades of LC3A and Beclin 1 immunohistochemical expression demonstrate the variation of autophagy at different phases of pediatric hepatic steatosis and varied disease etiology.

GATA6 identifies an immune-enriched phenotype linked to favorable outcomes in patients with pancreatic cancer undergoing upfront surgery

This study underscores GATA6's role in distinguishing classical and basal-like pancreatic ductal adenocarcinoma (PDAC) phenotypes. Retrospective studies associate GATA6 immunohistochemistry (IHC) expression with survival outcomes, warranting prospective validation. In a prospective treatment-naive cohort of patients with resected PDAC, GATA6 IHC proves a prognostic discriminator, associating high GATA6 expression with extended survival and the classical PDAC phenotype. However, GATA6's prognostic significance is numerically lower after gemcitabine-based neoadjuvant chemoradiotherapy compared to its significance in patients treated with upfront surgery. Furthermore, GATA6 is implicated in immunomodulation, although a comprehensive investigation of its immunological role is lacking. Treatment-naive PDAC tumors with varying GATA6 expression yield distinct immunological landscapes. Tumors highly expressing GATA6 show reduced infiltration of immunosuppressive regulatory Tcells and M2 macrophages but increased infiltration of immune-stimulating, antigen-presenting, and activated Tcells. Our findings caution against solely relying on GATA6 for molecular subtyping in clinical trials and open avenues for exploring immune-based combination therapies.

Frequent mutation of K-RAS in addition to BRAF V600E in Ameloblastoma – An immunohistochemical study

BackgroundAmeloblastoma is the most frequently encountered, enigmatic odontogenic tumor whose etiopathogenesis is still controversial. Understanding the pathogenic mechanism involved in Ameloblastoma and its proliferation aids in determining the best treatment option at an early stage. MAPK pathway are known to be active during tooth development, and also mutations in MAPK components have been identified in both benign and malignant tumors. The aim of this study was to evaluate the Immunohistochemical expression of biomarker BRAF V600E and K-RAS in Ameloblastoma and to examine if any, correlation exists between BRAF V600E and K-RAS expression. Methods30 formalin-fixed paraffin-embedded blocks of histopathologically diagnosed cases of Ameloblastoma were taken as samples. Immunohistochemistry using K-RAS and BRAF V600E antibody was performed and slides were evaluated both quantitatively and qualitatively using a quick score by an independent observer. ResultsK-RAS and BRAF V600E immunoexpression was evaluated and there is a significantly higher expression of K-RAS (mean score 6.20 ± 1.883) when compared with BRAF V600E (mean score 4.50 ± 2.271). BRAF V600E and K-RAS act independently in the pathogenesis of Ameloblastoma as the pattern of variation of BRAF V600E score was uneven when compared to K-RAS values. ConclusionOur data provide evidence that two independent mutation occurs in the same molecular pathway driving Ameloblastomas. But there is no correlation between K-RAS and BRAF V600E expression. Hence, combination therapy of K-RAS and BRAF V600E inhibitors can be helpful for the treatment of Ameloblastoma.

Immunohistochemical (IHC) Expression of p16 in Various Grades of Oral Squamous Cell Carcinoma (OSCC) with Snuff Use in Tertiary Care Hospitals of Peshawar

Oral squamous cell carcinoma (OSCC) is a significant health concern, with various factors influencing its development and progression. Understanding these factors, including p16 expression and clinicopathologic features, is crucial for improved diagnosis and treatment. Objective: To compare various grades of OSCC based on immunohistochemical expression of p16 and clinicopathologic parameters. Methods: The comparative cross-sectional study was conducted at the Department of Pathology, Peshawar Medical College (PMC), and Peshawar Dental College (PDC) from August 2020 to August 2021. It included 53 cases of OSCC with documented snuff use history. Tumor sections were stained with Hematoxylin and Eosin and underwent immunohistochemical staining for p16 expression. Sample size calculation utilized G Power software. Statistical analysis was performed using SPSS version 20.0, employing the Chi-Square test to assess categorical variables. Results: Among the 53 OSCC cases, the majority were male (66.0%) with ages ranging from 26 to 85 years, the most common age group being 51-70 years. The tongue was the primary site for OSCC development. Well-differentiated cases were predominant (64.2%), followed by moderate (20.8%) and poor grade cases (15.1%). However, no significant association was found between p16 expression and OSCC grades. Notably, p16 expression tended to be higher in snuff users and well-differentiated OSCC cases, although not statistically significant. Conclusions: Well-differentiated OSCC cases exhibited the highest expression of p16, followed by moderate and poorly differentiated cases. However, no significant correlation was observed between p16 expression and OSCC in snuff users.

Role of SOX10 Immunohistochemical Expression in Diagnosing Triple Negative Breast Cancer and Its Correlation With Clinicopathological Features.

Triple-negative breast cancer (TNBC) poses a diagnostic challenge for histopathologists due to the reduced frequency of breast-specific markers. SOX10 has emerged as a useful diagnostic marker for TNBC. The aim of our study was to determine the frequency of SOX-10 immunohistochemical (IHC) expression in our cohort and assess its correlation with clinicopathological and histological features. We included 72 primary TNBC cases. Specimens includedtru-cut biopsies and excision specimens. We stained whole slide sections of these specimens with SOX10 antibody and calculated its frequency (%) of expression and H-score. We applied the chi-square test to assess the correlation between SOX10 expression and clinicopathological and histological features such as the patient's age, specimen type, tumor size, histological type, histological grade, nuclear pleomorphism, mitotic count, tumor-infiltrating lymphocytes (TILs), necrosis, calcification, lymphovascular invasion (LVI), lymph node involvement, T stage, and N stage. SOX10 expression was observed in 42 (58.3%) cases with a median H-score of 57.5. The expression was significantly higher in tru-cut biopsy specimens as compared to excision specimens (73.5 vs 41.7%) and TILsnegative tumors as compared to TILs positive tumors (64.3% vs 27.3). Metaplastic carcinoma showed reduced expression when compared with non-metaplastic tumors (35.7% vs 63.8%), but statistical significance was not achieved. No correlation was observed with the patient's age, tumor size, histological type, histological grade, nuclear pleomorphism, mitotic count, necrosis, calcification, LVI, lymph node involvement, T stage, and N stage. SOX10 was expressed in more than half of the TNBC cases of our study which not only highlights its diagnostic utility but advocated its application in combination with other breast-specific markers. The expression didn't correlate with the majority of clinicopathological and histological features, but correlation with tru-cut biopsy specimens and absence of TILs draws attention towards possible roles of proper fixation and host immunity, respectively.

Prognostic Significance of NQO1 Expression in Non-neoplastic Esophageal Squamous Epithelium for Patients With Esophageal Cancer.

NAD(P)H dehydrogenase [quinone] 1 (NQO1), an antioxidant enzyme, confers resistance to anticancer agents. NQO1 C609T is a single-nucleotide polymorphism associated with reduced protein expression in the non-neoplastic esophageal squamous epithelium (ESE). This study aimed to investigate immunohistochemical NQO1 expression in non-neoplastic ESE and to elucidate its prognostic significance in patients with esophageal squamous cell carcinoma (ESCC) undergoing neoadjuvant therapy followed by esophagectomy. NQO1 expression in non-neoplastic ESE was determined in surgical specimens from 83 patients with ESCC using immunohistochemistry. The association between NQO1 expression and clinicopathological factors, and the prognostic significance of NQO1 expression for relapse-free survival (RFS) were statistically evaluated. Patients with complete loss or weak NQO1 expression and patients with moderate or strong NQO1 expression were classified into the NQO1-negative (n=29) and NQO1-positive (n=54) groups, respectively. The downstaging of T classification status after neoadjuvant therapy was significantly more frequent in the NQO1-negative group than in the NQO1-positive group (59% vs. 33%; p=0.036). The NQO1-negative group had significantly more favorable RFS than the NQO1-positive group (p=0.035). Multivariate survival analysis demonstrated that NQO1 negative expression had a favorable prognostic impact on RFS (HR=0.332; 95%CI=0.136-0.812; p=0.016). Immunohistochemical evaluation of NQO1 expression in non-neoplastic ESE has clinical utility for predicting patient prognosis after neoadjuvant therapy followed by esophagectomy and might be helpful for selecting candidates for adjuvant therapy to treat ESCC.