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Our previous studies have shown that BRCA1 gene deficiency caused by changes in the tumor such as low expression, deletion, loss of heterozygosity, etc., can be associated with the effectiveness of chemotherapy and the disease prognosis. However, even in the absence of these factors, the effectiveness of taxotere therapy was variable. This may be due to the availability of another BRCA1 gene somatic changes in the tumor tissue and their determination will help to define the personalize treatment strategy for each breast cancer patient. Here we investigated the entire spectrum germline and somatic mutation of coding region of the BRCA1 gene in tumor tissue. We obtained that absence of BRCA1 somatic mutation was associated with objective response on taxotere in the preoperative period. Germline mutations BRCA1: c.4837A>G (p.Ser1613Gly), c.999T>C (p.Ser333=), c.3548A>G (p.Lys1183Arg), c.3113A>G (p.Glu1038Gly), c.2612C>T (p.Pro871Leu), c.2311T>C (p.Leu771=), c.2082C>T (p.Ser694=) were associated with non-objective response on neoadjuvant chemotherapy (NAC), furthermore effect of chemotherapy was more than 80% without of these mutations. During chemotherapy, 13% of patients showed the appearance of 5 new BRCA1 mutations in the tumor and this is associated with a non-objective response to NAC by taxotere. Overall, our results suggest that it makes sense to take into account not only identified germline mutations, but also somatic changes in the BRCA1 gene when appointment taxotere.

In breast cancer, the tumor microenvironment plays a critical role in the tumor progression and responses to therapy. Tumor-associated macrophages (TAMs) are major innate immune cells in tumor microenvironment that regulate intratumoral immunity and angiogenesis by secretion of cytokines, growth factors as well as chitinase-like proteins (CLPs), that combine properties of cytokines and growth factors. YKL-39 is a chitinase-like protein found in human and absent in rodents, and its expression in TAMs and role in breast cancer progression was not studied to date. Here for the first time we demonstrate that YKL-39 is expressed on TAMs, predominantly positive for stabilin-1, but not by malignant cells or other stromal cells in human breast cancer. TGF-beta in combination with IL-4, but not IL-4 alone was responsible of the stimulation of the production of YKL-39 in human primary macrophages. Mechanistically, stabilin-1 directly interacted with YKL-39 and acted as sorting receptor for targeting YKL-39 into the secretory pathway. Functionally, purified YKL-39 acted as a strong chemotactic factor for primary human monocytes, and induced angiogenesis in vitro. Elevated levels of YKL-39 expression in tumors after neoadjuvant chemotherapy (NAC) were predictive for increased risk of distant metastasis and for poor response to NAC in patients with nonspecific invasive breast carcinoma. Our findings suggest YKL-39 as a novel therapeutic target, and blocking of its activity can be combined with NAC in order to reduce the risk of metastasis in breast cancer patients.

d-Glucuronyl C5-epimerase (GLCE) is one of key enzymes in heparan sulfate biosynthesis and possesses tumour-suppressor function in breast carcinogenesis. Here, we investigated a potential involvement of GLCE polymorphism(s) in breast cancer development in Siberian women population. Comprehensive analysis of SNP databases revealed GLCE rs3865014 (Val597Ile) missense polymorphism as the main significantly present in human populations. According the TaqMan-based SNP assay, allele distributions for the rs3865014 (A > G) were similar in healthy Siberian women (n = 136) and cancer patients (n = 129) (A0,73:G0,27) and intermediate between the European and Asian populations, while genotype distributions were different, with the increase of AG rate in breast cancer patients (OR = 1.76; 95% CI = 1.04–1.90; P(Y) = 0.035 χ2 = 4.44). Heterozygous AG genotype was associated with tumour size (OR = 3.67, P(Y) = 0.004), ER-negative tumours (OR = 3.25, P(Y) = 0.0028), triple-negative tumours (OR = 4.94, P(Y) = 0.015) but not menopausal status, PR and HER-2 status, local or distant metastasis. Homozygous GLCE genotypes (AA/GG) were more common for ER + PR + luminal A breast cancer (OR = 0.25, P(Y) = 0.031). Loss-of-heterozigosity was identified in 5 of 51 breast tumours and the loss of G allele was associated with the decreased GLCE expression. Epidemiologic data for the GLCE SNP in different racial/ethnic groups demonstrated high AG genotype rates as a risk factor not for breast cancer incidence but for poor prognosis of the disease. The obtained data suggest an involvement of GLCE rs3865014 in breast cancer development. Heterozygous AG genotype might be a risk factor for breast cancer susceptibility in Siberian women and is associated with aggressive ER-negative and triple-negative cancer subtypes.