METHODS: A total of 228 adult patients with GC or GEC were enrolled from Subang Jaya Medical Centre, Malaysia, for retrospective (210) and prospective study. All patients were subjected to the HER2 immunohistochemistry test using an FDA-approved, standardized test kit. Carcinomas scoring 2+ on immunohistochemistry were further tested with HER2 in situ hybridization (ISH) using an FDA-approved test kit.
RESULTS: The overall rate of HER2 positivity in the population studied was 24.6% (n = 56). The rate was significantly higher in men than in women (29.6 vs. 16.3%; p = 0.024). HER2 overexpression was significantly more common in diffuse type than in intestinal type of tumors (39.8 vs. 14.9%; p
CASE REPORT: A 58-year-old female presented with a 3-cm painless right axillary mass. Extensive radiological investigations that include mammography, ultrasonography of the breasts and positron emission tomography (PET) scan failed to conclude the primary site of the tumour. Histological examination of the lymph node revealed loosely cohesive sheets of poorly differentiated malignant cells, without discernible glandular or squamous differentiation. Immunohistochemically, the malignant cells exhibited diffuse immunoreactivity toward pan-cytokeratin and CK7, while leukocyte common antigen, S100 and CK20 were negative. A second panel of immunomarkers was carried out. The malignant cells expressed breast-specific markers (GATA-3, GCDFP-15 and mammaglobin), and were negative for ER, PR and TTF-1 immunohistochemistry. A diagnosis of OBC was rendered.
DISCUSSION: Breast primary must always be considered in the differential diagnosis in patients with sole presentation of axillary lymphadenopathy. The breast-specific immunomarkers play a pivotal role in the diagnosis of ER, PR-negative occult breast cancer.
Objective: This study aims to determine inter-laboratory variation in HER2 IHC testing through a slide-exchange program between five main reference laboratories.
Method: A total of 20 breast carcinoma cases with different known HER2 expression and gene status were selected by the central laboratory in five testing rounds. Three unstained tissue sections from each case were sent to participating laboratories, which immunostained and interpreted the HER2 immunohistochemistry result. One of the stained slides was sent to one designated participating laboratory for evaluation. Results were analyzed by the central laboratory.
Results: A complete concordance was achieved in six IHC-positive and six IHC-negative cases, its gene status of which was confirmed by in-situ-hybridization (ISH) study. The discordant results were observed in six equivocal cases, one negative case and one positive case with a concordance rate of 50-88.3%. Interestingly, the negative discordant case actually displays tumor heterogeneity. Good inter-observer agreement was achieved for all participating laboratories (k = 0.713-1.0).
Conclusion: Standardization of HER2 testing method is important to achieve optimum inter-laboratory concordance. Discordant results were seen mainly in equivocal cases. Intra-tumoral heterogeneity may impact the final HER2 IHC scoring. The continuous quality evaluation is therefore paramount to achieve reliable HER2 results.
METHODS: In this study, we determined the prevalence of germline APOBEC3B deletion and its association with breast cancer risk in a cross-sectional hospital-based Asian multi-ethnic cohort of 1451 cases and 1442 controls from Malaysia. We compared gene expression profiles of breast cancers arising from APOBEC3B deletion carriers and non-carriers using microarray analyses. Finally, we characterised the overall abundance of tumour-infiltrating immune cells in breast cancers from TCGA and METABRIC using ESTIMATE and relative frequency of 22 immune cell subsets in breast cancers from METABRIC using CIBERSORT.
RESULTS: The minor allelic frequency of APOBEC3B deletion was estimated to be 0.35, 0.42 and 0.16 in female populations of Chinese, Malay and Indian descent, respectively, and that germline APOBEC3B deletion was associated with breast cancer risk with odds ratios of 1.23 (95 % CI: [1.05, 1.44]) for one-copy deletion and 1.38 (95 % CI: [1.10, 1.74]) for two-copy deletion compared to women with no deletion. Germline APOBEC3B deletion was not associated with any clinicopathologic features or the expression of any APOBEC family members but was associated with immune response-related gene sets (FDR q values P
SIGNIFICANCE: NPC268 is the first and only EBV-positive cell line derived from a primary non-keratinizing, differentiated nasopharyngeal carcinoma, an understudied but important subtype in Southeast Asian countries. This model adds to the limited number of authentic EBV-positive lines globally that will facilitate mechanistic studies and drug development for NPC.