| Abstract: | The paper gives the results of studying the expression of the PTEN gene product by an immunohistochemical method, as well as deletion of the gene by fluorescence in situ hybridization in the tumor cells of 80 patients with triple-negative breast cancer (TNBC). The gene product was absent in the tumor cell nuclei in 56 products. The bulk of the remaining patients who showed a positive response had lobular carcinomas or tumors with an unidentified microscopic variant due to secondary posttherapeutic changes. Lobular carcinomas in a control group presented by patients without TNBC also contained the PTEN gene product. Therefore, all positively responding tumor cells failed to express basaloid markers and androgen receptors. The immunohistochemically detectable absence of the PTEN gene product is usually coupled with deletion at locus 10q23; however, in several cases the negative immunohistochemical reaction is associated with no deletion at the above locus, which suggests that there are mechanisms for PTEN gene dysregulation other than deletion in TNBC. The presence of the PTEN gene product in the tumor cells is associated with good prognosis in patients with TNBC. |
