Oct4 Is Not a Crucial Factor in Breast Invasive Ductal Carcinoma in Contrast to Recent Beliefs

We aimed to determine the frequency of Octamer binding transcription factor 4 (Oct4) expression in human invasive ductal carcinoma. 72 paraffin-embedded samples of breast cancer were enrolled. All blocks were stained for estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2(HER 2/neu), ki67, and Oct4 by immunohistochemistry (IHC) method. Of 72 enrolled cases, the mean age was 49.6±1.42 years. 18 (25%) of cases were luminal A, 14 (19.4%) were Her2 positive, 31 (43%) were luminal B, and 9 (12.5%) were triple-negative. IHC staining for Oct4 revealed no Oct4 expression in breast cancer samples. The staining was repeated twice, and seminoma was used as a positive control in each run. The results of both repeats were the same, and none of the examined samples showed Oct4 expression. We found no Oct4 expression in breast cancer samples examined in our study. We also did not find Oct4 expression in normal breast tissue. Our study is one of the few studies which has evaluated Oct4 expression in human breast cancer on tissue samples and is one of the least that has reported no expression of Oct4 in breast cancer.