Core Needle Biopsy Research Articles

Abstract 324: Comparison of xGen Exome Hyb Panel v2 (IDT) kit and Twist Exome 2.0 (TWIST) kit for whole exome sequencing optimization from low input and degraded FFPE samples

Abstract FFPE is the most common method used to store precious clinical samples at room temperature for extended periods (sometimes>15 years). FFPE samples are therefore one of the most commonly available samples that can be used for discovery and diagnosis. Whole Exome Sequencing (WES) is one of the most used NGS assays that is used for profiling somatic and tumor mutations. With future clinical trials moving towards less invasive collection methodology, core needle biopsy samples are becoming a method of choice. The FFPE fixation process leads to the degradation of nucleic acids due to cross-linkage and the availability of sufficient nucleic acid from CNB fixed samples for downstream NGS assays is becoming limited. Here we report a comparison of two Whole Exome capture kits from several degraded FFPE samples, NA12878, OncoSpan gDNA HD827 and SeraSeq Breast CNV mix gDNA samples using the xGen Exome Hyb Panel v2 (IDT) Kit and the Twist Exome 2.0 (TWIST) Kit. Libraries were prepared in triplicate at 50ng, and 10ng using the Ultra™ II DNA Library Prep (NEB) kit. Pre-capture libraries were evaluated to determine the total DNA library available for capture using the KAPA Library Quantification Kit (Roche) kit. The recommendations for input amount vary between the kits, with IDT recommending 500ng, and TWIST recommending 200ng per library. KAPA Library Quantification Kit kit was used to assess the nanomolar amounts of ligated libraries. Final libraries were pooled equimolar and then sequenced as 2 × 100bp Paired-end sequencing on the NovaSeq 6000 instrument to achieve a target of 150-300X overall coverage. The performance of each capture kit was evaluated on the number of libraries eligible for capture, percent duplication rate, median insert size, and mean target coverage. IDT capture had 49% of libraries eligible at recommended input of 500ng, with 34% of libraries generating between 100-499ng input and the remaining 17% failing to generate 100ng input for hybridization. TWIST capture had 83% of libraries eligible at recommended input of 200ng, with 4% of libraries generating between 50-199ng input and the remaining 13% failing to generate 50ng input for hybridization. Most notably, 96% of libraries at 50ng DNA input were eligible for TWIST capture, while only 46% of libraries at 50 ng DNA input were eligible for IDT capture. The average Q30 for IDT and TWIST capture were 93-94% respectively. Both IDT and TWIST capture kits produced similar duplication rates and average mean target coverage was comparable. Taken together, our testing shows that TWIST and IDT kits generated comparable sequencing metrics. However, the TWIST Kit outperforms the IDT Kit in percent eligible libraries qualifying for hybridization capture. TWIST Kit is a great qualifier for highly degraded FFPE samples, especially those with limited input DNA material. Citation Format: Rachel Rock, Nripesh Prasad, Melanie Robinson, Dinnen Wildman, Olivia Montoya, Michael Sykes, Boris Umylyn, Thomas Halsey. Comparison of xGen Exome Hyb Panel v2 (IDT) kit and Twist Exome 2.0 (TWIST) kit for whole exome sequencing optimization from low input and degraded FFPE samples [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 324.

Abstract 4200: A novel 3D culture platform, E-slice, retains intact tumor microenvironment and tumor infiltrating immune cells

Abstract Human cancer tissue is a complex ecosystem with heterogeneous cell types that communicate with each other dynamically to promote tumor progression and immune evasion. Hence, experimental systems that destroy or select for cancer cells in culture have often failed to accurately predict clinical responses of new drugs. Therefore, a technology that can retain the intact tumor microenvironment (TME) and accurately predict cancer patient’s response to anti-cancer treatments, including immunotherapies, will greatly benefit patients and dramatically reduce the cost of new drug development. E-slice is a proprietary 3D human tumor culture platform that maintains individual patient tumor’s unique ecosystem and the TME ex vivo for up to 30 days. It is generated by making thin sections of intact, fresh tumor tissues and culturing them in serum-free, defined media. As such, immune components and the TME in E-slices faithfully recapitulate human tumors ex vivo. We demonstrate that E-slices can be used to: 1) measure viability changes upon anti-cancer agent treatment longitudinally; 2) retain the native TME and tissue architecture since E-slices are never dissociated or artificially reconstituted; 3) culture any solid tumor types from patient needle biopsy cores or surgical samples, PDX, or mouse models; 4) perform high content drug screening on human tissues; 5) discover secreted biomarkers and to 6) discover or validate molecular mechanisms of action or therapy resistance; and 7) measure immunotherapy responses ex vivo from human tissues. Importantly, it has been shown to accurately predict individual patient treatment responses to chemotherapies and targeted therapies in 4-8 days, paving the way for evidence-based personalized treatment selections in a clinically actionable time frame. Furthermore, single cell RNA-sequencing analysis demonstrates that E-slices can retain the viability and molecular phenotypes of tumor infiltrating immune cells for up to 8 days ex vivo, providing a unique platform to study human tumor-immune interactions and evaluate efficacy of immune modulators on human tumor tissues ex vivo. Citation Format: Viridiana Leyva-Aranda, Thomas Gallup, Jose Maldonado, Corina Margain, Sang Yun, David Gallup, Min Kim, Kyuson Yun. A novel 3D culture platform, E-slice, retains intact tumor microenvironment and tumor infiltrating immune cells [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 4200.

Develop prediction model to help forecast advanced prostate cancer patients' prognosis after surgery using neural network.

The effect of surgery on advanced prostate cancer (PC) is unclear and predictive model for postoperative survival is lacking yet. We investigate the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database, to collect clinical features of advanced PC patients. According to clinical experience, age, race, grade, pathology, T, N, M, stage, size, regional nodes positive, regional nodes examined, surgery, radiotherapy, chemotherapy, history of malignancy, clinical Gleason score (composed of needle core biopsy or transurethral resection of the prostate specimens), pathological Gleason score (composed of prostatectomy specimens) and prostate-specific antigen (PSA) are the potential predictive variables. All samples are divided into train cohort (70% of total, for model training) and test cohort (30% of total, for model validation) by random sampling. We then develop neural network to predict advanced PC patients' overall. Area under receiver operating characteristic curve (AUC) is used to evaluate model's performance. 6380 patients, diagnosed with advanced (stage III-IV) prostate cancer and receiving surgery, have been included. The model using all collected clinical features as predictors and based on neural network algorithm performs best, which scores 0.7058 AUC (95% CIs, 0.7021-0.7068) in train cohort and 0.6925 AUC (95% CIs, 0.6906-0.6956) in test cohort. We then package it into a Windows 64-bit software. Patients with advanced prostate cancer may benefit from surgery. In order to forecast their overall survival, we first build a clinical features-based prognostic model. This model is accuracy and may offer some reference on clinical decision making.

Comprehensive evaluation of the relationship between biomarker profiles and neoadjuvant chemotherapy outcomes for breast cancer patients

BackgroundAccurately predicting the response to neoadjuvant chemotherapy (NAC) in breast cancer patients is crucial for guiding treatment strategies and enhancing clinical outcomes. Current studies have primarily focused on a limited set of biomarkers. More importantly, the results of many studies are in conflict. To address this, we conducted a comprehensive evaluation of the predictive value of a diverse range of clinically available molecular biomarkers in breast cancer, including HER2, ER, PR, TOPO II, EGFR, Ki67, CK5/6, AR, and p53. Additionally, we assessed changes in these biomarkers after NAC administration.MethodsOur study involved 189 patients with invasive breast cancer who underwent NAC at our institute. We examined biomarker profiles in core-needle biopsies taken before NAC and in surgical specimens obtained after NAC. We examined the association between these biomarkers and NAC outcomes, focusing on two main aspects: the rate of pathological complete response (pCR) and the reduction in tumor size. We used Chi-square and Mann-Whitney U tests to compare biomarker status changes between pCR and non-pCR patients. Linear regression analysis was employed to evaluate the relationship between biomarker status and tumor shrinkage rate. Additionally, we compared the expression status of these biomarkers before and after NAC using Chi-square and Wilcoxon signed-rank tests.Results and conclusionsOur results demonstrated significant differences in the expression levels of HER2, ER, PR, TOPO II, EGFR, and Ki67 between pCR and non-pCR patients, underscoring their potential as predictive markers for NAC outcomes. Importantly, our results have shed light on the contentious issue surrounding TOPO II in NAC outcome prediction. We have provided evidence that establishes a significantly positive association between TOPO II expression level and the pCR rate. Notably, tumor size was identified as a relevant predictive factor for achieving pCR. Regarding biomarker profiles, only Ki67 levels and TOPO II status exhibited changes following NAC, resolving previous controversies. While the ER and PR status remained unchanged, their expression values exhibited a slight but significant decrease post-NAC. Our results provide clarity and insights into the value and potential of using these biomarkers to predict NAC responses and prognosis in breast cancer patients.

Synchronous Low-Grade Central Osteosarcoma and Ewing Sarcoma: A Rare Case Report.

A 23-year-old female patient presented with radicular back pain, perineal numbness, and urinary retention. The patient was diagnosed with cauda equina syndrome and magnetic resonance imaging (MRI) of the spine revealed an enhancing osseous lumbar lesion causing severe central stenosis. A core needle biopsy of the lumbar spine showed microscopic features compatible with a small round blue cell tumor. CD99 and FLI1 were positive in the tumor cells. Next-generation sequencing demonstrated a EWSR1::FLI1 fusion. Given these findings, the spine lesion was diagnosed as Ewing sarcoma. The patient underwent surgical decompression of L2. On further workup, an MRI revealed an ill-defined enhancing mass of the right distal femur. This area was biopsied, demonstrating a fibro-osseous lesion with osteoblast proliferation containing nuclear atypia, low mitotic activity, and SATB2 positivity, diagnosed as low-grade central osteosarcoma (LGCOS). The patient underwent resection, which showed a classic LGCOS by histomorphology. Although fluorescence in-situ hybridization study for MDM2 gene amplification was negative, the overall findings are most consistent with LGCOS. These neoplasms are considered to be synchronous due to the presentation of each entity within 6 months. Considering the aggregate yearly incidence of Ewing sarcoma (approximately 1 case per 750 000 per year) and LGCOS (approximately 1 case per 10 million per year), the aggregate yearly probability of developing both of these genetically unrelated tumors in a single individual is 1 per 7.5 trillion per year, and it is likely such an event has never happened in the past.

Digital Validation in Breast Cancer Needle Biopsies: Comparison of Histological Grade and Biomarker Expression Assessment Using Conventional Light Microscopy, Whole Slide Imaging, and Digital Image Analysis.

Given the widespread use of whole slide imaging (WSI) for primary pathological diagnosis, we evaluated its utility in assessing histological grade and biomarker expression (ER, PR, HER2, and Ki67) compared to conventional light microscopy (CLM). In addition, we explored the utility of digital image analysis (DIA) for assessing biomarker expression. Three breast pathologists assessed the Nottingham combined histological grade, its components, and biomarker expression through the immunohistochemistry of core needle biopsy samples obtained from 101 patients with breast cancer using CLM, WSI, and DIA. There was no significant difference in variance between the WSI and CLM agreement rates for the Nottingham grade and its components and biomarker expression. Nuclear pleomorphism emerged as the most variable histologic component in intra- and inter-observer agreement (kappa ≤ 0.577 and kappa ≤ 0.394, respectively). The assessment of biomarker expression using DIA achieved an enhanced kappa compared to the inter-observer agreement. Compared to each observer's assessment, DIA exhibited an improved kappa coefficient for the expression of most biomarkers with CLM and WSI. Using WSI to assess prognostic and predictive factors, including histological grade and biomarker expression in breast cancer, is acceptable. Furthermore, incorporating DIA to assess biomarker expression shows promise for substantially enhancing scoring reproducibility.

Clinical significance of location of perineural cancer invasion detected on prostate needle core biopsy.

The clinical impact of site-specific perineural invasion (PNI) in prostate cancer remains poorly understood. We compared radical prostatectomy findings and oncologic outcomes in 434 patients with single-site PNI on systematic sextant biopsy. PNI was present in the right apex (n = 62; 14%), right mid (n = 70; 16%), right base (n = 89; 21%), left apex (n = 64; 15%), left mid (n = 58; 13%), and left base (n = 91; 21%). There were no significant differences in biopsy or prostatectomy findings, when comparing apex vs. mid vs. base PNI. Univariate analysis revealed that apex-localized PNI was associated with a significantly higher risk of progression, compared with base (P = 0.037) or mid/base (P = 0.024) PNI. Multivariable analysis showed that apex-localized PNI was an independent risk factor for progression (hazard ratio 2.049, P = 0.002). Among biopsies demonstrating PNI at one sextant site, apex-localized PNI is independently associated with poorer prognosis, though not worse histopathologic features on prostatectomy, compared with mid or base PNI.

Does the presence of macroscopic intralesional fat exclude malignancy? An analysis of 613 histologically proven malignant bone lesions.

To determine if macroscopic intralesional fat detected in bone lesions on CT by Hounsfield unit (HU) measurement and on MRI by macroscopic assessment excludes malignancy. All consecutive CT-guided core needle biopsies (CNB) of non-spinal bone lesions performed at a tertiary center between December 2005 and September 2021 were reviewed. Demographic and histopathology data were recorded. All cases with malignant histopathology were selected, and imaging studies were reviewed. Two independent readers performed CT HU measurements on all bone lesions using a circular region of interest (ROI) to quantitate intralesional fat density (mean HU < -30). MRI images were reviewed to qualitatively assess for macroscopic intralesional fat signal in a subset of patients. Inter-reader agreement was assessed with Cronbach's alpha and intraclass correlation coefficient. In 613 patients (mean age 62.9 years (range 19-95 years), 47.6% female), CT scans from the CNB of 613 malignant bone lesions were reviewed, and 212 cases had additional MRI images. Only 3 cases (0.5%) demonstrated macroscopic intralesional fat on either CT or MRI. One case demonstrated macroscopic intralesional fat density on CT in a case of metastatic prostate cancer. Two cases demonstrated macroscopic intralesional fat signal on MRI in cases of chondrosarcoma and osteosarcoma. Inter-reader agreement was excellent (Cronbach's alpha, 0.95-0.98; intraclass correlation coefficient, 0.90-0.97). Malignant lesions rarely contain macroscopic intralesional fat on CT or MRI. While CT is effective in detecting macroscopic intralesional fat in primarily lytic lesions, MRI may be better for the assessment of heterogenous and infiltrative lesions with mixed lytic and sclerotic components. Macroscopic intralesional fat is rarely seen in malignant bone tumors and its presence can help to guide the diagnostic workup of bone lesions. • Presence of macroscopic intralesional fat in bone lesions has been widely theorized as a sign of benignity, but there is limited supporting evidence in the literature. • CT and MRI are effective in evaluating for macroscopic intralesional fat in malignant bone lesions with excellent inter-reader agreement. • Macroscopic intralesional fat is rarely seen in malignant bone lesions.

Advancements in Diagnosis and Multimodal Treatment Strategies for Retroperitoneal Tumors: A Comprehensive Review.

Retroperitoneal tumors (RPTs) encompass both benign and malignant entities, constituting ~0.1% to 0.2% of all malignant tumors, of which 70% to 80% manifest malignancy. Predominantly, retroperitoneal sarcomas (RPS) represent the most prevalent subtype among RPT. With over 70 histologic forms identified, liposarcomas and leiomyosarcomas emerge as the primary constituents of RPS. Accurate diagnosis of RPTs necessitates preoperative core-needle biopsy and comprehensive imaging assessment. The current staging protocol for RPS relies on the eighth edition of the American Joint Committee on Cancer/TNM classification. Surgical excision remains the established gold standard for treating RPS. Therapeutic approaches vary according to the underlying pathophysiology. Although chemotherapy and radiotherapy exhibit efficacy in managing metastatic and recurrent unresectable RPS, their role in primary RPS remains unresolved, necessitating further clinical trials for validation. Concurrently, ongoing research explores the potential of targeted therapies and immunotherapy. This literature review aims to provide a comprehensive overview of existing research, delineating diagnostic pathways and optimal therapeutic strategies for RPT.

Cytomorphological Disparities in Invasive Breast Cancer Cells following Neoadjuvant Endocrine Therapy and Chemotherapy

Introduction: Neoadjuvant endocrine therapy (NAE) offers a breast-conserving surgery rate and clinical response rate similar to those of neoadjuvant chemotherapy (NAC), while presenting fewer adverse events and lower pathological complete response rates. The assessment of pathological response determines degenerative changes and predicts the prognosis of breast cancer treated with NAC. This study clarified the degenerative changes occurring in breast cancer following NAE. Methods: Our study encompassed two groups: NAE, consisting of 15 patients, and NAC, comprising 18 patients. Tissue samples were obtained from core needle biopsies and surgeries. Nuclear and cell areas were calculated using Autocell analysis. Furthermore, we assessed markers associated with microtubule depolymerization (KIF2A) and initiators of apoptosis (caspase-9). Results: In the NAC group, we observed significant increases in both cytoplasmic and cell areas. These changes in cytoplasm and cells were notably more pronounced in the NAC group compared to the NAE group. After treatment, KIF2A exhibited a decrease, with the magnitude of change being greater in the NET group than in the NAC group. However, no discernible differences were found in caspase-9 expression between the two groups. Conclusion: Our findings indicate that NAE induces condensation in cancer cells via cell cycle arrest or apoptosis. Conversely, NAC leads to cell enlargement due to the absence of microtubule depolymerization. These discrepancies underscore the importance of accounting for these distinctions when establishing criteria for evaluating pathological responses.

The Prognostic Value of Tumor Budding in Breast Biopsies and its Relationship with Survival: A Cross Sectional Study

Abstract: Background: In 1954 Imai described Tumor Budding (TB), as a tumor sprouting at the invasive tumor front of colorectal carcinomas. TB is associated with poor prognosis. TB has prognostic importance in invasive ductal carcinoma of the breast. Objective: The present study aims to examine TB in breast needle core biopsy specimens with invasive ductal type carcinoma, and its relationship with other clinicopathological parameters and overall survival. Materials and Methods: From February 2015 to December 2022, patients who had undergone breast carcinoma surgery at the Bolu Abant Izzet Baysal Training and Research Hospital and had preoperative needle core biopsies at the same center were retrospectively analyzed. Needle core biopsy slides were re-evaluated for TB. Tumor size, and nodal status, were retrieved from pathology reports. Overall survival was considered. Analysis of the data was done with statistical software (SPSS 18.0 for Windows, IBM Inc., Chicago, IL, USA). Results: 122 patients were enrolled in the study. The mean age of the study and control groups were 55±12 years and 54±11 years, respectively. TB was identified in 68 (55%) patients; the rest 54 (45%) patients didn’t have any TB. The median value of the metastatic axillary lymph node in the TB absent group was 0 (0-51); in the TB group was 1 (0-21), and this was statistically significant (p=0.03). Lymphovascular invasion was detected in 33 patients (48.5%) in the TB present group and in 14 patients (25.9%) in the TB absent group. That was statistically significant (p=0.01). In the overall survival analysis, mean survival times were lower in the TB group compared to the TB absent group, but it was not statistically significant (p=0.33). Conclusion: In conclusion, tumor budding is a robust prognostic indicator; therefore, assessing tumor budding especially in core needle biopsy specimens will be very helpful for individual treatment options.

Immune pathogenesis of idiopathic granulomatous mastitis: from etiology toward therapeutic approaches.

Idiopathic granulomatous mastitis (IGM) is a noncancerous, chronic inflammatory disorder of breast with unknown causes, posing significant challenges to the quality of life due to its high refractoriness and local aggressiveness. The typical symptoms of this disease involve skin redness, a firm and tender breast mass and mastalgia; others may include swelling, fistula, abscess (often without fever), nipple retraction, and peau d'orange appearance. IGM often mimics breast abscesses or malignancies, particularly inflammatory breast cancer, and is characterized by absent standardized treatment options, inconsistent patient response and unknown mechanism. Definite diagnosis of this disease relies on core needle biopsy and histopathological examination. The prevailing etiological theory suggests that IGM is an autoimmune disease, as some patients respond well to steroid treatment. Additionally, the presence of concurrent erythema nodosum or other autoimmune conditions supports the autoimmune nature of the disease. Based on current knowledge, this review aims to elucidate the autoimmune-favored features of IGM and explore its potential etiologies. Furthermore, we discuss the immune-mediated pathogenesis of IGM using existing research and propose immunotherapeutic strategies for managing this condition.

Uses and limitations of small-volume biopsies for the diagnosis of lymphoma.

Although surgical biopsy remains the gold standard for the diagnosis of lymphoma, small-volume biopsies including fine-needle aspiration and core needle biopsy are increasingly being used as a first line diagnostic tool. Small-volume biopsies are safe, rapid and cost effective; however, diagnostic utility varies by lymphoma subtype. It is important for pathologists and clinicians to recognize both the strengths and limitations of such biopsies.

Papillary renal neoplasm with reverse polarity is biologically and clinically distinct from eosinophilic papillary renal cell carcinoma.

Papillary renal neoplasm with reverse polarity (PRNRP) is a recently described indolent entity with distinct features and its recognition from other oncocytic/eosinophilic papillary renal cell carcinoma (ePRCC) has important prognostic implications. ABCC2, a renal drug transporter, is overexpressed in aggressive PRCCs. In this study, we compared the clinicopathological parameters and the biological ABCC2 expression between PRNRP and ePRCC. PRNRP (n = 8) and ePRCC (n = 21) cases were selected from resection specimens and corresponding clinicopathological data were collected. ABCC2 immunohistochemical (IHC) staining was performed and ABCC2 staining patterns were classified as negative, cytoplasmic, and brush-border. RNA in-situ hybridization (ISH) was used to assess ABCC2 transcript levels. All eight PRNRP cases had weak cytoplasmic ABCC2 IHC reactivity; however, they showed no detectable ABCC2 transcripts on RNA ISH. In comparison, 76% (16/21) of ePRCCs showed ABCC2 IHC brush-border expression and significantly higher ABCC2 RNA ISH transcript levels (p < 0.001). Additionally, the ePRCC group showed a significantly larger tumor size (p = 0.004), higher WHO/ISUP grade (p < 0.001), and stage (p = 0.044). None of the PRNRP cases showed disease progression, while 9.5% (2/21) ePRCCs had disease progression. PRNRP is clinically and biologically distinct from ePRCC. Hence, it is crucial to differentiate between these two entities, particularly in needle core biopsies.

Stratified application of gene expression in diagnosis of thyroid nodules

Objective: To investigate the value of BRAF V600E and multigene detection and stratified application for the diagnosis of thyroid nodules. Methods: A total of 1 117 patients with thyroid nodules resection at Nanjing Gulou Hospital from December 2020 to July 2022 were enrolled in the study. Fine needle aspiration (FNA) and core biopsy samplings were performed for cytopathologic examination and genetic testings; the findings were combined with BSRTC classification. The diagnostic performance of BRAF V600E and multigene detection were compared. Results: Among the 1, 117 patients who underwent thyroid nodules resection, 285 were male and 832 were female, with a median age of 46 years (range: 24-76 years). Postoperative histopathologic examination confirmed 1 040 cases of thyroid cancer and 77 cases of benign nodules. The sensitivity (87.0% vs. 80.8%, P<0.01) and diagnostic accuracy (87.9% vs. 82.1%, P<0.01) of multigene detection were significantly higher than those of BRAF V600E detection. The result of multigene detection showed that BRAF V600E mutation was the most common finding, followed by CCDC6-RET (E1-E12) fusion, ETV6-NTRK3 fusion, and KRAS mutation. Multigene detection had a higher sensitivity (81.9% vs. 72.8%, P<0.01) and lower cancer risk in wild-type (47.6% vs. 57.7%, P=0.069) than BRAF V600E detection in BSRTCⅠ-Ⅴ lesions. Compared with BRAF V600E detection, multigene had no significant difference of sensitivity in BSRTC Ⅰ lesions, but significantly higher sensitivity (86.3% vs 74.0%, P<0.01) in BSRTC Ⅲ lesions. Conclusions: Genetic detection can be used as an effective tool for the diagnosis of thyroid nodules. A stratified application of molecular markers in the diagnosis of thyroid nodules is proposed. Combined with FNA, single gene or multigene detection both can effectively assist in the diagnosis of thyroid nodules. Moreover, multigene detection is superior to single gene detection. For BSRTC Ⅲ lesion with wild-type BRAF, multigene detection can be considered with a repeated FNA.

A Nationwide Study on HER2-Low Breast Cancer in South Korea: Its Incidence of 2022 Real World Data and the Importance of Immunohistochemical Staining Protocols.

Notable effectiveness of trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2 (HER2)-low advanced breast cancer (BC) has focused pathologists' attention. We studied the incidence and clinicopathologic characteristics of HER2-low BC, and the effects of immunohistochemistry (IHC) associated factors on HER2 IHC results. The Breast Pathology Study Group of the Korean Society of Pathologists conducted a nationwide study using real-world data on HER2 status generated between January 2022 and December 2022. Information on HER2 IHC protocols at each participating institution was also collected. Total 11,416 patients from 25 institutions included in this study. Of these patients, 40.7% (range, 6.0% to 76.3%) were classified as HER2-zero, 41.7% (range, 10.5% to 69.1%) as HER2-low, and 17.5% (range, 6.7% to 34.0%) as HER2-positive. HER2-low tumors were associated with positive estrogen receptor and progesterone receptor statuses (p < 0.001 and p < 0.001, respectively). Antigen retrieval times (≥ 36 minutes vs. < 36 minutes) and antibody incubation times (≥ 12 minutes vs. < 12 minutes) affected on the frequency of HER2 IHC 1+ BC at institutions using the PATHWAY HER2 (4B5) IHC assay and BenchMark XT or Ultra staining instruments. Furthermore, discordant results between core needle biopsy and subsequent resection specimen HER2 statuses were observed in 24.1% (787/3,259) of the patients. The overall incidence of HER2-low BC in South Korea concurs with those reported in previously published studies. Significant inter-institutional differences in HER2 IHC protocols were observed, and it may have impact on HER2-low status. Thus, we recommend standardizing HER2 IHC conditions to ensure precise patient selection for targeted therapy.

Ki-67 Testing in Breast Cancer: Assessing Variability With Scoring Methods and Specimen Types and the Potential Subsequent Impact on Therapy Eligibility.

Abemaciclib was originally FDA approved for patients with ER-positive/HER2-negative breast cancer with Ki-67 expression ≥20%. However, there were no guidelines provided on which specimen to test or which scoring method to use. We performed a comprehensive study evaluating the variation in Ki-67 expression in breast specimens from 50 consecutive patients who could have been eligible for abemaciclib therapy. Three pathologists with breast expertise each performed a blinded review with 3 different manual scoring methods [estimated (EST), unweighted (UNW), and weighted (WT) (WT recommended by the International Ki-67 in Breast Cancer Working Group)]. Quantitative image analysis (QIA) using the HALO platform was also performed. Three different specimen types [core needle biopsy (CNB) (n=63), resection (RES) (n=52), and axillary lymph node metastasis (ALN) (n=50)] were evaluated for each patient. The average Ki-67 for all specimens was 14.68% for EST, 14.46% for UNW, 14.15% for WT, and 11.15% for QIA. For the manual methods, the range between the lowest and highest Ki-67 for each specimen between the 3 pathologists was 8.44 for EST, 5.94 for WT, and 5.93 for UNW. The WT method limited interobserver variability with ICC1=0.959 (EST ICC1=0.922 and UNW=0.949). Using the aforementioned cutoff of Ki-67 ≥20% versus <20% to determine treatment eligibility, the averaged EST method yields 20 of 50 patients (40%) who would have been treatment-eligible, versus 15 (30%) for the UNW, 17 (34%) for the WT, and 12 (24%) for the QIA. There was no statistically significant difference in Ki-67 among the 3 specimen types. The average Ki-67 difference was 4.36 for CNB vs RES, 6.95 for CNB versus ALN, and RES versus ALN (P=0.93, 0.99, and 0.94, respectively). Our study concludes that further refinement in Ki-67 scoring is advisable to reduce clinically significant variation.

26 (PB-7) Poster Spotlight - Core Needle Biopsy outperforms Fine-Needle Aspiration Cytology in diagnosing axillary lymph node metastasis in breast cancer patients

26 (PB-7) Poster Spotlight - Core Needle Biopsy outperforms Fine-Needle Aspiration Cytology in diagnosing axillary lymph node metastasis in breast cancer patients

Applications of artificial intelligence in prostate cancer histopathology.

The diagnosis of prostate cancer (PCa) depends on the evaluation of core needle biopsies by trained pathologists. Artificial intelligence (AI) derived models have been created to address the challenges posed by pathologists' increasing workload, workforce shortages, and variability in histopathology assessment. These models with histopathological parameters integrated into sophisticated neural networks demonstrate remarkable ability to identify, grade, and predict outcomes for PCa. Though the fully autonomous diagnosis of PCa remains elusive, recently published data suggests that AI has begun to serve as an initial screening tool, an assistant in the form of a real-time interactive interface during histological analysis, and as a second read system to detect false negative diagnoses. Our article aims to describe recent advances and future opportunities for AI in PCa histopathology.

Reliable Prostate Cancer Risk Mapping From MRI Using Targeted and Systematic Core Needle Biopsy Histopathology.

To compute a dense prostate cancer risk map for the individual patient post-biopsy from magnetic resonance imaging (MRI) and to provide a more reliable evaluation of its fitness in prostate regions that were not identified as suspicious for cancer by a human-reader in pre- and intra-biopsy imaging analysis. Low-level pre-biopsy MRI biomarkers from targeted and non-targeted biopsy locations were extracted and statistically tested for representativeness against biomarkers from non-biopsied prostate regions. A probabilistic machine learning classifier was optimized to map biomarkers to their core-level pathology, followed by extrapolation of pathology scores to non-biopsied prostate regions. Goodness-of-fit was assessed at targeted and non-targeted biopsy locations for the post-biopsy individual patient. Our experiments showed high predictability of imaging biomarkers in differentiating histopathology scores in thousands of non-targeted core-biopsy locations (ROC-AUCs: 0.85-0.88), but also high variability between patients (Median ROC-AUC [IQR]: 0.81-0.89 [0.29-0.40]). The sparseness of prostate biopsy data makes the validation of a whole gland risk mapping a non-trivial task. Previous studies i) focused on targeted-biopsy locations although biopsy-specimens drawn from systematically scattered locations across the prostate constitute a more representative sample to non-biopsied regions, and ii) estimated prediction-power across predicted instances (e.g., biopsy specimens) with no patient distinction, which may lead to unreliable estimation of model fitness to the individual patient due to variation between patients in instance count, imaging characteristics, and pathologies. This study proposes a personalized whole-gland prostate cancer risk mapping post-biopsy to allow clinicians to better stage and personalize focal therapy treatment plans.