Study of the level of tumor markers and mutations in the BRCA1/2 genes in breast cancer patients with metachronous tumors.

Abstract

e12563 Background: Primary multiple malignant tumors are more common in women with breast cancer (BC). However, the difference in the frequency of mutations in the BRCA1/2 genes in metachronous BC tumors has not been fully studied, and there are also conflicting data on the increase in the level of specific tumor markers in this category of patients. Methods: The survey included 58 patients with BC with II-III clinical stages of the disease, of which metachronous tumors in terms of 6 months or more were found in 26 (44.8%) patients, among them metachronous cancer of the second breast - in 14 (53 .8%), cancer of the body of the uterus - in 7 (26.9%) and ovarian cancer - in 5 (19.2%) patients. In the control group of 32 (55.2%) patients with initially diagnosed BC, with the same stages of the disease. Tumor markers were determined in the peripheral venous blood of patients using reagent kits for ELISA analysis produced in Russia. The study of mutations in the BRCA1/2 genes was performed using sequencing on the Illumina MiSeq platform in tumor samples from waxed histological blocks. Library sequencing was performed using MiSeq Reagent Kit v2. Results: ELISA analysis of the level of tumor markers in patients with BC showed that with the development of metachronous cancer, the studied markers were more common than in the control group. In patients with metachronous tumors, elevated levels of CA-125 occurred in 10 (38.5%) patients, CA-15-3 - in 8 (30.8%), CA-19-9 - in 4 (15.4%), AFP - in 5 (19.2%), CEA - in 6 (23.1%). In the control group, CA-125 was found in 6 (18.8%) patients, CA-15-3 - in 5 (15.6%), CA-19-9 - in 2 (6.3%), AFP - in 1 (3.1%), CEA - in 2 (6.3%). Excess levels significant for diagnosis were observed for CA-125 and CA-15-3 in both groups of patients, but in the group of patients with BC with metachronous tumors, these figures were approximately 2 times higher. In the rest of the patients, the oncomarkers under consideration did not reach values significant for diagnosis. The total incidence of patients with clinically significant germline variants in the BRCA1/2 genes in the control group was 5 (15.6%), of which there were predominantly patients with an increased frequency in the population (5382insC, 4154del4, C61G). The total incidence of BC patients with metachronous tumors with germline and somatic variants in the BRCA1/2 genes was 16 (61.5%), with an increased frequency in the same population, mainly in patients with germline mutations. Conclusions: Dynamic study of the level of tumor markers CA-125 and CA-15-3 and CA-19-9 may be useful in the preventive examination of patients with a history of BC as an early diagnosis of the development of metachronous tumors in this category of patients. The most important diagnostic unfavorable factor in the development of metachronous tumors in the examined BC patients was germline mutations in the BRCA1/2 genes.