Paraffin-embedded Tissue Blocks Research Articles

Prevalence of HER-2 expression and correlation with clinicopathological features in gynecological cancer: A single-center retrospective study in China.

e17500 Background: Targeted therapy for human epidermal growth factor receptor 2 (HER2) has become a standard of care in several HER2-expressing solid tumors. Nonetheless, there remains an unmet need for effective treatment, for instance, anti-HER2 antibody-drug conjugates (ADCs), in advanced stage gynecological cancer. In this context, we presented a retrospective study on the incidence of HER2 expression in primary gynecological cancer based on a single-center data from southwestern China. Methods: Paraffin-embedded tumor tissue blocks, clinicopathological, and survival data of gynecological cancer patients were collected from Chongqing University Cancer Hospital. HER2 IHC scoring was carried out according to the updated ASCO/CAP guidelines for breast and gastroesophageal adenocarcinoma by two pathologists independently. Data analysis was performed using SPSS v.24. Results: A total of 104 cases of cervical cancer, 102 cases of endometrial cancer and 103 cases of ovarian cancer were included between 2019 and 2023. HER2 expression was detected in 31.7% samples, with scores of 1+, 2+, and 3+ in 23.9% (74/309: 36/104, 16/102, 22/103), 5.8% (18/309: 7/104, 7/102, 4/103), and 1.9% (6/309: 2/104, 1/102, 3/103) of patients, respectively. Notably, ultra-low HER2 expression with incomplete and faint staining in ≤10% of tumor cells was observed in 41.1% (127/309: 37/104, 53/102, 37/103) of patients. Metastasis and lymphovascular invasion were associated with elevated HER2 expression in endometrial cancer (p=0.037, 0.040, respectively), while a larger tumor size was associated with elevated HER2 expression in cervical cancer (p=0.004). However, no positive association between HER2 status and overall survival (OS) was found in cervical, endometrial or ovarian cancer. In our cohort, metastasis was the only risk factor related to reduced OS of gynecological cancer patients by COX regression analysis (HR=14.00, 95%CI=1.32-148.21, p=0.028). Conclusions: Our data revealed a considerable number of patients with HER2-low and ultra-low gynecological cancer. It might represent a significant portion in real-world scenarios and warrant more consideration in selecting candidates for HER2-targeted ADCs, especially for those with relapsed or refractory conditions. Given the inherent challenge in interpretation, the study highlights the necessity for a consensus on evaluating HER2 immuno-staining results in gynecological cancer. Clinical trial information: MR-50-23-019676 . [Table: see text]

The diagnostic potentiality of the RNA aptamer against progesterone receptor isolated by crush and soak (CRUSOAK)-SELEX.

Aptamers are a class of molecular recognition elements that exhibit high binding affinity and specificity against their respective targets. In view of the many advantages aptamers harbor over their counterpart antibodies, we were impelled to isolate an RNA aptamer against progesterone receptor, particularly its DNA binding domain. A total of eight SELEX cycles were executed against the recombinant Progesterone Receptor DNA-binding domain (PR DBD). The RNA-protein complex in the gel shift assay was subjected to crush and soak method to elute the binders prior to conventional sequencing, the step of which was based upon to coin the term CRUSOAK-SELEX. The sequencing revealed three different classes of sequences, with one class termed, PRapt-3, showing the strongest binding against PR DBD. The dissociation constant of PRapt-3 RNA aptamer was estimated at 380nM ± 35nM. PRapt-3 was successfully used to develop aptamer-based diagnostic assays such as ELASA, aptamer-based dot blot, and aptamer-based western blot. The prominent highlight is the performance of the aptamer in aptacytostaining, which was unachievable with antibodies. Compared to its counterpart antibodies, PRapt-3 has a better penetration capacity in aptahistostaining using the formalin-fixed paraffin-embedded (FFPE) breast cancer cells and tissue blocks. This study represents the first ever demonstration of an aptamer against progesterone receptor and its diagnostic capacity.

Correlation of tumor-associated macrophage density and proportion of M2 subtypes with the pathological stage of colorectal cancer.

Colorectal cancer (CRC) is a prevalent global malignancy with complex prognostic factors. Tumor-associated macrophages (TAMs) have shown paradoxical associations with CRC survival, particularly concerning the M2 subset. We aimed to establish a simplified protocol for quantifying M2-like TAMs and explore their correlation with clinicopathological factors. A cross-sectional study included histopathological assessment of paraffin-embedded tissue blocks obtained from 43 CRC patients. Using CD68 and CD163 immunohistochemistry, we quantified TAMs in tumor stroma and front, focusing on M2 proportion. Demographic, histopathological, and clinical parameters were collected. TAM density was significantly higher at the tumor front, with the M2 proportion three times greater in both zones. The tumor front had a higher M2 proportion, which correlated significantly with advanced tumor stage (P = 0.04), pathological nodal involvement (P = 0.04), and lymphovascular invasion (LVI, P = 0.01). However, no significant association was found between the M2 proportion in the tumor stroma and clinicopathological factors. Our study introduces a simplified protocol for quantifying M2-like TAMs in CRC tissue samples. We demonstrated a significant correlation between an increased M2 proportion at the tumor front and advanced tumor stage, nodal involvement, and LVI. This suggests that M2-like TAMs might serve as potential indicators of disease progression in CRC, warranting further investigation and potential clinical application.

Abstract PS11-07: High prevalence of HER2-Low and AR expression in breast cancer brain metastases provide novel therapeutic options

Abstract Background: Although survival rates for patients with advanced breast cancer (BC) have improved overall, rates of BC brain metastases (BCBM) have increased over the past two decades, occurring in up to 15% to 30% of patients. BCBM greatly reduce quality of life and overall survival (OS) and are now the leading cause of BC patient mortality. Patients with primary HER2+ and triple negative BC (TNBC) are at highest risk for BM. Locoregional therapy with surgery and radiation are currently standard of care (SOC), but these treatments have significant morbidity and BCBM progressing despite these interventions are hard to treat. Systemic therapies to reduce cognitive impairment and increase survival are desperately needed, particularly in HER2-negative patients. Currently, immune checkpoint inhibitors (ICIs) and small molecules such as PARP inhibitors are among the limited systemic options that have BCBM activity in HER2-negative BC. However, the benefit of these therapies is limited to a select group of patients. For example, androgen receptor (AR) is expressed in 60-80% of all BC and, in our recently completed clinical trial (NCT03206203), patients with AR+ metastatic TNBC treated with carboplatin +/- atezolizumab received no clinical benefit from the addition of atezolizumab. Alternatives to ICIs are needed for patients with AR+ TNBC. HER2-low (H2L) BC is a newly defined subset of HER2-negative BC with a HER2 immunohistochemical (IHC) score of 1+ ( >10%) or 2+/in situ hybridization (ISH) negative phenotype. Recent clinical trials have demonstrated significant clinical benefit from novel HER2 antibody-drug conjugates (ADCs) in treating H2L BC. Trastuzumab-deruxtecan (T-Dxd), a HER2-directing ADC (topoisomerase I inhibitor conjugated to a humanized HER2-targeted antibody) was recently FDA approved as the first targeted therapy to treat H2L BC and can penetrate the blood–brain barrier. DESTINY-Breast04 demonstrated notable PFS and OS benefit of T-DXd compared to SOC in patients with H2L metastatic BC and included 61 patients with BCBM (results anticipated shortly). The overall rates of AR and H2L expression in patients with BCBM is unknown. The goal of this study is to investigate the prevalence of AR and HER2-low expression in a large cohort of BCBM treated at our institution. Methods: We retrospectively assessed rates of H2L and AR positivity (AR+) among patients with BCBM whose treatment included surgery at our institution between 2005-2023. Results were correlated with clinical receptor status (HR+/HER2-, HER2+/HR+, HER2+/HR- and TNBC) and clinical characteristics. Results of ER, PR, and HER2 testing performed for clinical purposes on the brain metastases and primary tumors were obtained from pathology reports. We retrieved formalin-fixed paraffin-embedded tissue blocks of the brain metastases and performed IHC for AR (SP107) and prognostic markers for cases with missing data. Results: We identified 101 cases of BCBM. Based on clinical prognostic markers, BCBM subtypes were HR+/HER2- (22%), HR+/HER2+ (14%), HER2+/HR- (21%) and TNBC (43%). Forty-five percent of the BCBM (n=45) were AR+ ( >10%) and 24% (n=24) demonstrated > 50% AR+. Among tumors with >50% AR+, 42% (n=10) are H2L (7 HR+[30%] and 3 TNBC [13%]). Forty-two percent of BCBM were H2L. Among the HER2-negative BCBM (n= 66), 64% (n=42) were H2L, including 23 of 44 TNBC (52%) and 19 of 22 HR+ (86)%. Fifteen percent of BMBC changed clinical subtype from the primary, including conversion to TNBC and H2L. Conclusion: AR+ positive (24% > 50% expression) and HER2-Low expressing (42%) tumors represent a significant proportion of our BCBM cohort providing exciting new options for treatment. Trials re-evaluating AR antagonists in combination with SOC utilizing high AR+ thresholds may benefit patients with BCBM. At least 10% of BCBM are both H2L and demonstrate >50% AR positivity providing the rationale for the combination of ADCs such as T-DXd and AR-targeted therapies for BCBM. Citation Format: Guadalupe Garcia, Paula Gonzalez-Ericsson, Brian Lehmann, Bret Mobley, Jennifer Pietenpol, Laura Kennedy, Ben Park, Melinda Sanders. High prevalence of HER2-Low and AR expression in breast cancer brain metastases provide novel therapeutic options [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 PS11-07.

Quantitative assessment Cyclooxygenase – 2 immunohistochemical expression in different grades of oral epithelial dysplasia

Oral leukoplakia (OLP) is one the most common potentially malignant disorders account 0.2 to 4.9% of malignant transformation and dysplastic lesions vary from 3-6% this rate of malignant conversion depends on the different grades of epithelial dysplasia. Recent literature suggests that increased levels of COX-2 in potentially malignant disorders and malignant tumors show prominent genetic evidence in tumorigenesis. Assessment of Cyclooxygenase-2 – 2 (COX-2) immunohistochemical expression in different grades of oral epithelial dysplasia. Materials and Methodology A total of forty formalin-fixed, paraffin-embedded tissue blocks were obtained from departmental archives which are histopathological diagnoses of different grades of oral epithelial dysplasia each grade ten samples was included. Stained with COX-2 and positive cells were counted and tabulated for statistical analysis. Results Comparison between genders in oral leukoplakia males was more when compared with females. The mean age in mild epithelial dysplasia was more when compared with moderate and severe epithelial dysplasia. Expression of COX-2 was increased from mild to severe epithelial dysplasia increases. The mean number of positive cells was increased. A comparison of all groups was not statistically significant (p≥0.05). Conclusion: Oral leukoplakia (OLP) is one the most common potentially malignant disorders which accounts for 0.2 to 4.9% of malignant transformation. COX-2 can be used for early detection and prognostic makers in different grades of oral epithelial dysplasia. Keywords: Cyclooxygenase, Expression, Oral leukoplakia, Potentially malignant transformation

Demographics and Pathomorphology of Ameloblastoma: A 9 Year Retrospective Review at a Tertiary Health Care Centre in North-Central Nigeria

Ameloblastoma is a benign but locally invasive neoplasm that arises from odontogenic epithelium of the dental lamina. It is classified into the conventional, unicystic, extraosseous/peripheral and metastasizing variants. It is the most common odontogenic tumour in Nigeria and other developing countries. It affects individuals of all ages, has a peak of occurrence in the fourth and fifth decades with no sex predilection. The Mandible is the most commonly affected site and the conventional variant is predominant. The aim of this study is to document the demographics and Pathomorphology of ameloblastoma diagnosed at the Jos University Teaching Hospital over the past nine years. There is no previous documentation of the pattern of this tumour in the North-central region of Nigeria making this study relevant. This is a retrospective observational review of all cases of ameloblastoma diagnosed histologically at the Jos University Teaching Hospital between January 1st 2015 to December 31st 2023. Materials utilized consisted of patient clinical case files, electronic histopathology result records, histopathology glass slides and formalin fixed paraffin embedded tissue blocks. The patient age, sex, anatomic location of tumour in the Jaw/face and pathomorphological features were recorded for all cases. The data obtained was analysed using Epi-info 7 (version 3.5.4) and Microsoft-Excel. Results were presented in tables and charts. Fifty one cases of ameloblastoma were diagnosed during the 9 years of review. Their ages ranged between 6 and 65 years with a mean age of 30.9±13.8 years and a peak of occurrence in the third decade. There were 29 males and 22 females with a male to female ratio (M:F) of 1.3:1. Ninety-two percent of cases occurred in the mandible and 8% in the maxilla. The conventional variant accounted for 72.5% of cases and the unicystic variant 27.5%. The follicular type accounted for 64.8% of cases of conventional ameloblastoma. Ameloblastoma occurred more commonly in males with a peak in the third decade. A vast majority of cases involved the mandible and the conventional type was predominant. This demographic pattern supports existing evidence that ameloblastoma occurs more commonly in males and in relatively younger patients in Africa.

Evaluation of stromal myofibroblasts in oral submucous fibrosis and its malignant transformation: An immunohistochemical study.

Oral submucous fibrosis (OSF) is a precancerous lesion, with oral squamous cell carcinoma (OSCC) being the most prevalent malignancy affecting the oral mucosa. The malignant transformation of OSF into OSCC is estimated to occur in 7-13% of cases. Myofibroblasts (MFs) play pivotal roles in both physiological and pathological processes, such as wound healing and tumorigenesis, respectively. This study aimed to explore the involvement of MFs in the progression of OSF and its malignant transformation. In total, 94 formalin-fixed paraffin-embedded tissue blocks were collected, including normal oral mucosa (NOM; n = 10), early-moderate OSF (EMOSF; n = 29), advanced OSF (AOSF; n = 29), paracancerous OSF (POSF; n = 21), and OSCC (n = 5) samples. Alpha-smooth muscle actin was used for the immunohistochemical identification of MFs. NOM exhibited infrequent expression of MFs. A higher staining index of MFs was found in AOSF, followed by EMOSF and NOM. Additionally, a significant increase in the staining index of MFs was found from EMOSF to POSF and OSCC. The staining index of MFs in NOM, EMOSF, AOSF, POSF, and OSCC was 0.14 ± 0.2, 1.69 ± 1.4, 2.47 ± 1.2, 3.57 ± 2.6, and 8.86 ± 1.4, respectively. All results were statistically significant (P < 0.05). The expression of MFs exhibited a gradual increase as the disease progressed from mild to malignant transformation, indicating the contributory role of MFs in the fibrogenesis and potential tumorigenesis associated with OSF.

PD-L1 Immunohistochemical Expression in Endometrial Carcinoma: Egyptian Cross-Sectional Study.

Endometrial carcinoma (EC) is the most common cancer of the female genital tract. According to the recently evolved strategies of cancer immunotherapy, immune checkpoints inhibitors are one of the most crucial strategies. Programmed Death Ligand 1 (PD-L1) is an important immune checkpoint regulator. PD-L1 antibodies have shown efficacy in clinical trials of some malignancies. Some of these antibodies have been approved for clinical usage by the Food and Drug Administration (FDA). This retrospective study included a total of 100 ECs, collected from archived, formalin-fixed, paraffin-embedded tissue blocks of hysterectomy specimens of Egyptian females. The samples were immunohistochemically analyzed for PD-L1 expression (in both tumor cells; TCs and tumor infiltrating leucocytes; TILs) by a semiquantitative score (0 to 4), with cutoff points of (0: <1% of the cells, 1: 1% to 4%, 2: 5% to 9%, 3: 10% to 49%, and 4: ≥ 50%). Membranous staining only was considered positive. PD-L1 was highly expressed in ECs (67% TCs+ and 61% TILs+), with statistically significant relationships with age, lympho-vascular space invasion (LVSI) and TILs score (P = 0.006, 0.016 and <0.005 respectively). However, no statistically significant relationships were detected between PD-L1 expression and the following parameters: histological type, histological grade, pathological stage (pT) or FIGO stage, myometrial, cervical, adnexal/serosal, parametrial involvements and nodal metastasis, as well as ESMO risk stratification system. Moreover, statistically significant relationships were achieved when correlating TILs score with tumor grade and LVSI (P = 0.034 and 0.012 respectively). Also, comparing endometrial hyperplasia (EH) PD-L1 and TCs PDL1 median scores achieved statistically significant relationship (P = 0.001). Our results concluded that PD-L1 expression was greater in both TCs and TILs in a subgroup of patients that have advanced age, LVSI and are TILs-rich, identifying them as potential candidates for anti-PD-1/PD-L1 immunotherapy.

Immunohistochemical and Clinicopathologic Profiling of Pituitary Adenomas at a Nigerian Tertiary Hospital

Background: Pituitary adenoma is the most common pituitary tumour and the third most common intracranial tumour worldwide. Only a few studies have been done in Africa on the immunohistochemical expression pattern and clinicopathologic presentations of the different hormonal subtypes of pituitary adenomas. Objective: To evaluate the immunohistochemical hormonal profiles and clinicopathologic behaviour of pituitary adenomas diagnosed within ten years at the Lagos University Teaching Hospital, Lagos, Nigeria. Methods: In this 10-year retrospective, cross-sectional study, all cases of pituitary adenomas diagnosed at the hospital mentioned above between 1 January 2009 and 31 December 2018 were analysed. Their paraffin-embedded tissue blocks were stained with haematoxylin and eosin and then with immunostains for growth hormome (GH), adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH), follicular stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL), using their standard immunohistochemistry protocols. Results: Seventy pituitary adenoma cases were studied. The male-to-female ratio of the patients was 1.6:1. The median age was 45 years, and the peak age of occurrence was the fifth decade for both sexes. Most were null cell adenomas (44.7%) and FSH-beta gonadotrophs (22.9%). The least diagnosed were thyrotroph (1.4%) and corticotroph adenomas (1.4%). Most of the adenomas were macroadenomas, and the most common presenting symptom was visual impairment. Conclusion: Pituitary adenoma is commoner in males in their 5th decade of life at the Lagos University Teaching Hospital, Lagos, Nigeria. The null cell adenoma is the commonest type of pituitary adenoma diagnosed in the center, and the majority of the patient diagnosed with pituitary adenoma present late with complications of visual impairment.

High-Density Polyethylene Custom Focusing Lenses for High-Resolution Transient Terahertz Biomedical Imaging Sensors.

Transient terahertz time-domain spectroscopy (THz-TDS) imaging has emerged as a novel non-ionizing and noninvasive biomedical imaging modality, designed for the detection and characterization of a variety of tissue malignancies due to their high signal-to-noise ratio and submillimeter resolution. We report our design of a pair of aspheric focusing lenses using a commercially available lens-design software that resulted in about 200 × 200-μm2 focal spot size corresponding to the 1-THz frequency. The lenses are made of high-density polyethylene (HDPE) obtained using a lathe fabrication and are integrated into a THz-TDS system that includes low-temperature GaAs photoconductive antennae as both a THz emitter and detector. The system is used to generate high-resolution, two-dimensional (2D) images of formalin-fixed, paraffin-embedded murine pancreas tissue blocks. The performance of these focusing lenses is compared to the older system based on a pair of short-focal-length, hemispherical polytetrafluoroethylene (TeflonTM) lenses and is characterized using THz-domain measurements, resulting in 2D maps of the tissue refractive index and absorption coefficient as imaging markers. For a quantitative evaluation of the lens effect on the image resolution, we formulated a lateral resolution parameter, R2080, defined as the distance required for a 20-80% transition of the imaging marker from the bare paraffin region to the tissue region in the same image frame. The R2080 parameter clearly demonstrates the advantage of the HDPE lenses over TeflonTM lenses. The lens-design approach presented here can be successfully implemented in other THz-TDS setups with known THz emitter and detector specifications.

Abstract 3623: Quantifying pharmacodynamic markers of radioligand therapies in tumor by multiplex immunofluorescence and automated quantitative analysis (AQUA) algorithms

Abstract Purpose: Due to profound clinical successes observed with radioligand therapies (RLT) across multiple cancers coupled with advances in drug handling and delivery logistics recently, clinical trials investigating RLTs are on the rise. Ionizing radiation produced by radioisotopes linked to antibodies causes double-stranded breaks either directly or via generation of reactive oxygen species. This type of DNA damage is associated with an increase in proteins mediating cell cycle arrest (e.g., p21/CIP1) and repairing damaged DNA (e.g., CHK2 and γH2Ax). Additionally, proliferating cells (identifiable by Ki67) are most susceptible to ionizing radiation as DNA is exposed during the mitotic phase of the cell cycle. We incorporated these biologically verified markers into a multiplexed fluorescence immunohistochemistry (mFIHC) assay for robust quantitation of the pharmacodynamic activity of RLTs and gain insights into the DNA damage response in on-treatment tumor core biopsies. Study Design: We designed a novel mFIHC assay incorporating antibodies to p21, pCHK2, γH2Ax, Ki67, CK to quantitatively characterize DNA damage across five tumor indications of commercially available ovarian cancer, colorectal cancer, gastric cancer, endometrial (uterine) cancer, and breast cancer formalin-fixed paraffin-embedded (FFPE) tissue blocks. We successfully validated this mFIHC assay using automated staining (Bond RX), imaging (PhenoImager HT), and combined with hypothesis-driven spatial profiling algorithms (e.g., AQUA Technology). Results: Sensitivity and specificity were confirmed on known positive and negative controls. Reproducibility and precision were observed across instruments, operators, and independent experiments for all markers The frequency of p21 ranged from 5% - 8%, pCHK2 from 3% - 36%, pH2Ax from 0% - 8%, Ki67 from 4% - 61%, and CK cells ranged from 25% to 87%. Over 56 unique parameters were evaluated. The prevalence of p21, pCHK2, and γH2Ax ranged from 0% to &amp;gt;30% across five tumor indications tested and were highly concordant. Conclusion: The validated mFIHC assay examines the expression of proteins mediating cell cycle arrest and DNA damage in tumor and stromal cells. This panel may be used to further understand the complexity of DNA damage response pathways in tumor and non-tumor areas in the context of RLT clinical trials. Citation Format: James Santos, Virginia Nyanchama, Vincent Romanet, Ernesta Dammassa, Lisa Kattenhorn, Ying Huang, Jimmie Lim, Xun Li, James Deeds, Lori Iaconis, Emmanuel Pacia, Margaret McLaughlin, Naveen Dakappagari, Jennifer Bordeaux. Quantifying pharmacodynamic markers of radioligand therapies in tumor by multiplex immunofluorescence and automated quantitative analysis (AQUA) algorithms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3623.

Abstract 196: In vitro modeling of pediatric solid tumor lung metastases

Abstract Metastasis remains the main cause of death in pediatric cancer patients with the lung being one of the most common affected organs. Our inability to cure these patients is largely due to insufficient knowledge about tumor and metastatic niche plasticity, while existing models are not fully effective in mirroring the response seen in clinical setting. Our goal is to overcome these limitations by establishing in vitro lung metastasis models using tumor/lung organoid co-cultures to study lung infiltration of pediatric solid tumors. We successfully established patient-derived lung organoids from pediatric lung tissue and characterized them according to the presence and the localization of the respective lung epithelial cell types. Co-culture conditions of lung organoids with PDX-derived Ewing sarcoma and osteosarcoma cells were optimized and models established, while the establishment of models for other pediatric solid tumor entities is ongoing. We have observed infiltration of the lung organoids by tumor cells, and our preliminary findings suggest distinct patterns of infiltration among different tumor entities. Furthermore, we have performed single-cell RNA sequencing analysis on these co-cultures in comparison to the parental lung organoids and tumor cells, aiming to uncover the specific signaling pathways activated in the lung metastatic niche in response to tumor cell invasion. Additionally, experiments using conditioned medium suggest that the lung organoid secretome is sufficient to induce homing of osteosarcoma and Ewing sarcoma cells to the organoids, with the CXCL12/CXCR4 signaling axis as a prime candidate driver. To ascertain the extent to which our in vitro model recapitulates the in vivo lung metastatic niche, we performed spatial transcriptomics (using VISIUM/10X Genomics) on formalin-fixed paraffin-embedded (FFPE) tissue blocks of paired primary tumors and lung metastasis samples for Ewing sarcoma and osteosarcoma. Comprehensive data analysis is currently ongoing, which will instruct a stepwise incorporation of additional factors into our modular organoid co-culture model, resulting in a better representation of the lung metastatic niche. Further, the analysis of patient-derived material will elucidate the spatial organization of solid tumor lung metastases and contribute to the identification of signaling pathways implicated in lung infiltration. In conclusion, our study not only unravels the complexities of pediatric solid tumor metastasis, but also lays the foundation for exploring the anti-metastatic potential of pathway-specific compounds targeting tumor/lung interactions using the established in vitro lung metastasis models. This study is supported by grant 35353-B of the Austrian Science Fund. Citation Format: Martha Zylka, Christoph Hafemeister, Lukas Watzke, Ulrike Mann, Didier Surdez, E. Alejandro Sweet-Cordero, Bernadette Liegl-Atzwanger, Matthias Dettmer, Matthias Farlik, Florian Halbritter, Martin Metzelder, Heinrich Kovar, Branka Radic-Sarikas. In vitro modeling of pediatric solid tumor lung metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 196.

High rate of high-risk human papillomavirus among benign and breast cancer patients in Ethiopia.

There have been numerous studies that showed the presence of human papillomavirus (HPV) in breast cancer; nonetheless, there is ongoing debate regarding their association. Given few studies in Ethiopia, we aimed to investigate the magnitude of HPV infection in Ethiopian breast cancer patients. A total of 120 formalin-fixed paraffin-embedded (FFPE) tissue blocks were obtained, and basic demographic, clinical, and histological data were collected from medical records. DNA was extracted from archived FFPE breast tissue specimens using GeneRead DNA FFPE Kit. The AnyplexTM II HPV28 Detection Kit (Seegene, Korea) was used to detect HPV by following the manufacturer's instructions. The SPSS Version 25 was used to enter and analyze data. Among the 120 study participants; HPV (both high-risk and low-risk) was detected in 20.6% of breast cancer and 29.6% of non-malignant breast tumors. The most common genotype was the high-risk HPV 16 genotype. The frequency of HPV was nearly 10-fold higher in estrogen receptor-positive than ER-negative breast cancer. The percentage of HPV in the luminal (luminal A and luminal B) breast cancer subtypes was also much higher than in the non-luminal subtypes (HER-2 enriched and triple-negative breast cancer). This study did not find a significant difference in HPV expression between breast cancer and non-malignant breast tumors; however, the higher percentage of HPV in ER-positive compared to ER-negative breast cancer warrants further attention.

A clinicopathological analysis of 151 odontogenic tumors based on new WHO classification 2022: A retrospective cross-sectional study

Background: Odontogenic tumors are a diverse group of lesions with a variety of clinical behavior and histopathologic subtypes, from hamartomatous and benign to malignant. The study aimed to examine the clinical and pathological features of odontogenic tumors in Baghdad over the last 11 years (2011–2021). Materials and Methods: The present retrospective study analyzed all formalin-fixed, paraffin-embedded tissue blocks of patients diagnosed with an odontogenic tumor that were retrieved from archives at a teaching hospital/College of Dentistry in Baghdad University, Iraq, between 2011 and 2021. The diagnosis of each case was confirmed by examining the hematoxylin and eosin stained sections by two expert pathologists. Data from patients' case sheets were collected, including age, gender, location, and histopathological information. The type of lesions was evaluated based on the World Health Organization's most recent classification (March 2022). Results: There were 151 odontogenic tumor during this period. The most common type (39.1%) was Solid ameloblastoma. The mandibular tumors (76.8%) were more than the maxillary tumors (23.2%). The female to male ratio was 1.1:1. The most cases are found between the 2nd and 5th decades of life. Conclusions: Solid ameloblastoma was the most common odontogenic tumor, while primordial odontogenic tumor was the rarest, Odontogenic tumors were slightly more common in females than in males, the most common cases occur in the mandible., the outcome of the study gives valuable information regarding the patients' profile and type of odontogenic tumors over 11 years, which could aid in the early diagnosis and enhance the intervention.

Diagnosis of Mucormycosis Using Frozen Section, Histopathology, Culture, and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) Techniques: A Comparative Study.

Mucormycosis usually occurs in immunocompromised patients or those with uncontrolled diabetes. Along the third wave of SARS-CoV-2, an associated angioinvasive opportunistic infection with Mucor, a life-threatening fungal infection, was rampant and emerging. With an increase in the usage of steroids in the COVID scenario, the rate of mucormycosis did take a rapid and alarming increase in King Edward Memorial Hospital, Pune, India. Any delay in the diagnosis and management of the disease was life-threatening. The most conventional methods to diagnose mucormycosis are microbiological culture and histopathology of the tissue. The microbiological culture method plays an important role in the diagnosis of mucormycosis. However, the technique is labour-intensive, taking seven to eight days. Histopathology leads to false-negative reports if the tissue is not biopsied from representative sites. On the other hand, molecular methods are rapid, reliable, and applicable to different body samples, such as tissue, paraffin-embedded tissue blocks, plasma, and urine. We aimed to use a reverse transcriptase polymerase chain reaction (RT-PCR) method to detect Mucor in plasma samples. Due to a lack of availability of fresh samples, nucleic acid was extracted from the tissue sections of 69 cases diagnosed as Mucor by histopathology. These samples were subjected to RT-PCR using the MucorGenius kit (Pathonostics, Maastricht, Netherlands). A total of 57 tissue samples were sent for culture, and 49% of our cases were positive by culture and equally by RT-PCR. There was 80% sensitivity and 76% specificity between culture and PCR techniques. However, the use of blood/plasma for RT-PCR for early diagnosis of mucormycosis will be the method of choice.

The spectrum of TP53 mutations in Rwandan patients with gastric cancer

BackgroundGastric cancer is the sixth most frequently diagnosed cancer and third in causing cancer-related death globally. The most frequently mutated gene in human cancers is TP53, which plays a pivotal role in cancer initiation and progression. In Africa, particularly in Rwanda, data on TP53 mutations are lacking. Therefore, this study intended to obtain TP53 mutation status in Rwandan patients with gastric cancer.ResultsFormalin-fixed paraffin-embedded tissue blocks of 95 Rwandan patients with histopathologically proven gastric carcinoma were obtained from the University Teaching Hospital of Kigali. After DNA extraction, all coding regions of the TP53 gene and the exon–intron boundary region of TP53 were sequenced using the Sanger sequencing. Mutated TP53 were observed in 24 (25.3%) of the 95 cases, and a total of 29 mutations were identified. These TP53 mutations were distributed between exon 4 and 8 and most of them were missense mutations (19/29; 65.5%). Immunohistochemical analysis for TP53 revealed that most of the TP53 missense mutations were associated with TP53 protein accumulation. Among the 29 mutations, one was novel (c.459_477delCGGCACCCGCGTCCGCGCC). This 19-bp deletion mutation in exon 5 caused the production of truncated TP53 protein (p.G154Wfs*10). Regarding the spectrum of TP53 mutations, G:C > A:T at CpG sites was the most prevalent (10/29; 34.5%) and G:C > T:A was the second most prevalent (7/29; 24.1%). Interestingly, when the mutation spectrum of TP53 was compared to three previous TP53 mutational studies on non-Rwandan patients with gastric cancer, G:C > T:A mutations were significantly more frequent in this study than in our previous study (p = 0.013), the TCGA database (p = 0.017), and a previous study on patients from Hong Kong (p = 0.006). Even after correcting for false discovery, statistical significance was observed.ConclusionsOur results suggested that TP53 G:C > T:A transversion mutation in Rwandan patients with gastric cancer is more frequent than in non-Rwandan patients with gastric cancer, indicating at an alternative etiological and carcinogenic progression of gastric cancer in Rwanda.

High Concordance of Different Assays in the Determination of Homologous Recombination Deficiency-Associated Genomic Instability in Ovarian Cancer.

Poly(ADP-ribose) polymerase inhibitors (PARPi) have shown promising clinical results in the treatment of ovarian cancer. Analysis of biomarker subgroups consistently revealed higher benefits for patients with homologous recombination deficiency (HRD). The test that is most often used for the detection of HRD in clinical studies is the Myriad myChoice assay. However, other assays can also be used to assess biomarkers, which are indicative of HRD, genomic instability (GI), and BRCA1/2 mutation status. Many of these assays have high potential to be broadly applied in clinical routine diagnostics in a time-effective decentralized manner. Here, we compare the performance of a multitude of alternative assays in comparison with Myriad myChoice in high-grade serous ovarian cancer (HGSOC). DNA from HGSOC samples was extracted from formalin-fixed paraffin-embedded tissue blocks of cases previously run with the Myriad myChoice assay, and GI was measured by multiple molecular assays (CytoSNP, AmoyDx, Illumina TSO500 HRD, OncoScan, NOGGO GISv1, QIAseq HRD Panel and whole genome sequencing), applying different bioinformatics algorithms. Application of different assays to assess GI, including Myriad myChoice, revealed high concordance of the generated scores ranging from very substantial to nearly perfect fit, depending on the assay and bioinformatics pipelines applied. Interlaboratory comparison of assays also showed high concordance of GI scores. Assays for GI assessment not only show a high concordance with each other but also in correlation with Myriad myChoice. Thus, almost all of the assays included here can be used effectively to assess HRD-associated GI in the clinical setting. This is important as PARPi treatment on the basis of these tests is compliant with European Medicines Agency approvals, which are methodologically not test-bound.

A radiologic-pathologic study of the histopathologic variants of ameloblastomas and their proliferation indices

Objectives: This study aimed to analyze the clinicoradiologic features and Ki-67 proliferation indices between the histopathologic variants of ameloblastomas (ABs) for possible associations. Study design: The diagnosis and histopathologic variant were confirmed for all cases by experienced Oral and Maxillofacial Pathologists. Immunohistochemistry for Ki-67 was performed on the most representative formalin-fixed paraffin-embedded tissue block. Demographic, clinical data and radiologic features were analyzed from patient records and available radiographic examinations. The investigators were blinded to the histopathologic variant and proliferation index when the clinicoradiologic features were assessed. Results: The current study included 116 cases of AB in the final sample. The indolent behavior of the unicystic variant was supported by their low proliferation index and slow growth paired with low frequencies of cortical destruction, loss of teeth, root resorption, and encroachment on anatomical structures. In contrast, the comparatively high proliferation index of the plexiform variant correlated with their fast growth and pain. Furthermore, high radiologic frequencies of cortical destruction, loss of teeth, and encroachment of surrounding anatomical structures supported their more aggressive clinical course. Conclusion: Statistically significant differences were noted between certain variants and Ki-67, location, borders, locularity, and cortical destruction, providing better insight into their biological behavior.

Pathological investigation of high pathogenicity avian influenza H5N8 in captive houbara bustards (Chlamydotis undulata), the United Arab Emirates 2020

At the end of 2020, an outbreak of HPAI H5N8 was registered in captive African houbara bustards (Chlamydotis undulata) in the United Arab Emirates. In order to better understand the pathobiology of this viral infection in bustards, a comprehensive pathological characterization was performed. A total of six birds were selected for necropsy, histopathology, immunohistochemistry, RNAscope in situ hybridization and RT-qPCR and nanopore sequencing on formalin-fixed and paraffin-embedded (FFPE) tissue blocks. Gross lesions included mottled and/or hemorrhagic pancreas, spleen and liver and fibrinous deposits on air sacs and intestine. Necrotizing pancreatitis, splenitis and concurrent vasculitis, hepatitis and fibrino-heterophilic peritonitis were identified, microscopically. Viral antigens (nucleoprotein) and RNAs (matrix gene) were both detected within necro-inflammatory foci, parenchymal cells, stromal cells and endothelial cells of affected organs, including the myenteric plexus. Molecular analysis of FFPE blocks successfully detected HPAI H5N8, further confirming its involvement in the lesions observed. In conclusion, HPAI H5N8 in African houbara bustards results in hyperacute/acute forms exhibiting marked pantropism, endotheliotropism and neurotropism. In addition, our findings support the use of FFPE tissues for molecular studies of poorly characterized pathogens in exotic and endangered species, when availability of samples is limited.

The Clinicopathological Correlation of KRAS Mutation and PTEN Expression Status in Primary and Metastatic Colorectal Carcinoma.

Colorectal cancer (CRC) researchhas identified a consistent loss of PTEN expression in both primary tumors and metastasis, highlighting its potential role in this disease. However, the impact of PTEN on downstream proteins of KRAS mutation, namely p-AKT, p-ERK, and p65 (NFkB), remains unknown. This study aims to explore the inhibitory effect of PTEN on KRAS downstream proteins and its correlation with pathological features in CRC patients. From January 1, 2015, to December 31, 2021, 86 CRC cases were collected from governmental and private laboratories in the Duhok province. Formalin-fixed, paraffin-embedded tissue blocks were obtained, and the study involved histopathological analysis, immunohistochemistry of PTEN, AKT, ERK, and P65 markers, and molecular analysis of the KRAS gene. Among the 86 cases, there were 46 males (53.5%) and 40 females (46.5%), with an equal distribution between right colon and left colon/rectum. Tumors larger than 5cm were observed in 47 cases, predominantly displaying a polypoid or ulcerated growth pattern. Most cases were moderately differentiated adenocarcinomas, with stages II and III being the most prevalent 31 cases (36%) and 34 cases (39.5%) respectively. Significant associations were found between PTEN, ERK expressions, and tumor location in the right colon (P=0.031 and P=0.009 respectively). Tumor size correlated with P65 expression (P=0.042). KRAS mutation showed a positive relationship with the type of tumor growth (P=0.035). Tumor grade increased with KRAS mutations (P=0.043). PTEN expression correlated significantly with ERK and AKT markers (P=0.018 and 0.035 respectively). P65 exhibited an association with KRAS mutation (P=0.034). The study revealed PTEN expression in association with the inhibition of AKT and ERK, and the absence of KRAS gene mutation. Conversely, PTEN is not expressed with the positively reactive P65 and the presence of KRAS mutation. This study contributes valuable insights into the complex interplay between PTEN expression, KRAS mutation, and downstream signaling pathways in CRC. It suggests potential avenues for further research and therapeutic strategies in the context of CRC treatment.