Breast cancer may be classified into luminal A, luminal B, HER2+/ER-, basal-like and normal-like subtypes based on gene expression profiling or immunohistochemical (IHC) characteristics. The main aim of the present study was to classify breast cancer into molecular subtypes based on immunohistochemistry findings and correlate the subtypes with clinicopathological factors. Two hundred and seventeen primary breast carcinomas tumor tissues were immunostained for ER, PR, HER2, CK5/6, EGFR, CK8/18, p53 and Ki67 using tissue microarray technique. All subtypes were significantly associated with Malay ethnic background (p=0.035) compared to other racial origins. The most common subtypes of breast cancers were luminal A and was significantly associated with low histological grade (p<0.000) and p53 negativity (p=0.003) compared to HER2+/ER-, basal-like and normal-like subtypes with high histological grade (p<0.000) and p53 positivity (p=0.003). Luminal B subtype had the smallest mean tumor size (p=0.009) and also the highest mean number of lymph nodes positive (p=0.032) compared to other subtypes. All markers except EGFR and Ki67 were significantly associated with the subtypes. The most common histological type was infiltrating ductal carcinoma, NOS. Majority of basal-like subtype showed comedo-type necrosis (68.8%) and infiltrative margin (81.3%). Our studies suggest that IHC can be used to identify the different subtypes of breast cancer and all subtypes were significantly associated with race, mean tumor size, mean number of lymph node positive, histological grade and all immunohistochemical markers except EGFR and Ki67.
At the present time, the differentiation between follicular thyroid carcinoma (FTC) and adenoma can be made only postoperatively and is based on the presence of capsular or vascular invasion. The ability to differentiate preoperatively between the malignant and benign forms of follicular thyroid tumors assumes greater importance in any clinical setting. The PAX8-PPARG translocation has been reported to occur in the majority of FTC. In this study, a group of 60 follicular thyroid neoplasms [18 FTC, 1 Hurthle cell carcinoma (HCC), 24 follicular thyroid adenomas (FTA), 5 Hurthle cell adenomas (HCA), and 12 follicular variants of papillary thyroid carcinomas (FV-PTC)] were analyzed to determine the prevalence of the PAX8-PPARG translocation by fluorescence in situ hybridization. The PAX8-PPARG translocation was detected in 2/18 FTC (11.1%). In addition, 2/18 (11.1%) FTC and 1/5 (20%) HCA showed 3p25 aneusomy only. The frequency of the translocation detected in the study was lower compared to the earlier studies conducted in Western countries. This might be attributed to the ethnic background and geographic location. Detection of either the PAX8-PPARG translocation or the 3p25 aneusomy in FTC indicates that these are independent genetic events. It is hereby concluded that 3p25 aneusomy or PAX8-PPARG translocation may play an important role in the molecular pathogenesis of follicular thyroid tumors.