Contribution of BRCA1 5382insC mutation to triplene-gative and luminal types of breast cancer in Ukraine.

PURPOSE: The gene BRCA1 plays a key role in DNA repair in breast and ovarian cell lines and this is considered one of target tumor suppressor genes in same line of cancers. The 5382insC mutation is among the most frequently detected in patients (Eastern Europe) with triple-negative breast cancer (TNBC). In Ukraine, there is not enough awareness of necessity to test patients with TNBC for BRCA1 mutations. That is why this group of patients is not well-studied, even through is known the mutation may affect the course of disease. METHODS: The biological samples of 408 female patients were analyzed of the 5382insC mutation in BRCA1. We compared the frequency of the 5382insC mutation in BRCA1 gene observed in Ukraine with known frequencies in other countries. RESULTS: For patients with TNBC, BRCA1 mutations frequency was 11.3%, while in patients with luminal types of breast cancers, the frequency was 2.8%. Prevalence of 5382insC among TNBC patients reported in this study was not different from those in Tunisia, Poland, Russia, and Bulgaria, but was higher than in Australia and Germany. CONCLUSION: The BRCA1 c.5382 mutation rate was recorded for the first time for TNBC patients in a Ukrainian population. The results presented in this study underscore the importance of this genetic testing of mutations in patients with TNBC. Our study supports BRCA1/2 genetic testing for all women diagnosed with TNBC, regardless of the age of onset or family history of cancer and not only for women diagnosed with TNBC at <60y.o., as guidelines recommend.

Response to neoadjuvant chemotherapy in breast cancer: do microRNAs matter?

BACKGROUND: Conventionally, breast cancer (BC) prognosis and prediction of response to therapy are based on TNM staging, histological and molecular subtype, as well as genetic alterations. The role of various epigenetic factors has been elucidated in carcinogenesis. However, it is still unknown to what extent miRNAs affect the response to neoadjuvant chemotherapy (NACT). This pilot study is focused on evaluating the role of miR-34a, miR-124a, miR-155, miR-137 and miR-373 in response to NACT. METHODS: That was a prospective study enrolling 34 patients with histologically confirmed BC of II-III stages. The median age of patients was 53 (47-59.8) years old, 70.6% of whom were HR-positive. MiRs levels were measured in the primary tumor before and after NACT. The response to therapy was assessed after surgery using the Miller-Payne scoring system. To establish the role of miRs in modulating response to NACT the Cox model was applied for analysis. RESULTS: BC demonstrated a great variability of miRs expression before and after NACT with no strong links to tumor stage and molecular subtype. Only miR-124a and miR-373 demonstrated differential expression between malignant and normal breast tissues before and after therapy though these distinctions did not impact response to NACT. Besides miR-124a and miR-137 levels after NACT were found to be dependent on HR status. While miR-124a levels increased (p = 0.021) in the tumor tissue, the expression of miR-137 was downregulated (p = 0.041) after NACT in HR positive BC. CONCLUSIONS: The study revealed differences in miR-124a and miR-373 expression after NACT in primary BC tissues. Although miRs levels did not impact the response to NACT, we found miR-124a and miR-137 levels to be related to hormonal sensitivity of BC.

MAPK/ERK signal pathway alterations in patients with Langerhans Cell Histiocytosis.

BACKGROUND: Clinical outcomes of Langerhans cell histiocytosis (LCH) are highly variable. It has been suggested that mitogen-activated protein kinase (MAPK) /extracellular signal-regulated kinases (ERK) signaling pathway might be activated in LCH patients. MATERIALS AND METHODS: We investigated KRAS, BRAF and NRAS mutations in patients with LCH by qPCR. RESULTS: Eight adult patients with LCH were treated at the National Cancer Institute, Kiev, Ukraine. Five patients received chemo plus radiation therapy and three patients received only chemotherapy, resp. (p < 0.05). All patients received LCH-I study protocol, six cycles in average. A BRAF c.1799T > A, p. V600E mutation was detected in 25% (2/8) of cases - 1 patient had an early relapse in 6 months, and 1 patient - stable disease. We did not find any BRAF, KRAS or NRAS mutations in three patients with late relapses (in 15, 24 and 46 months). Notably, KRAS mutations were not revealed in any LCH samples. The NRAS c.182A > G, p. Q61R mutation was found in two cases - one patient had LCH transformed to Hodgkins lymphoma, one patient had a refractory disease. Time to relapse rate (TTR) in patients with and without BRAF V600E gene mutation was 13 vs. 28 months, resp. (p < 0.05). TTR was 31.3 vs. 6.41 months in patients with absence and presence of NRAS mutation, p < 0.05. Multivariate analysis showed the presence of NRAS Q61R mutation was associated with poor event-free survival in LCH patients with HR of 6.1 (95% CI 0.2-12.6; p = 0.008). CONCLUSION: BRAF and NRAS mutations in LCH suggest a possibility of the disease being driven by the activation of the MAPK/ERK pathway. These oncogenic mutations provide new opportunities in understanding LCH pathogenesis and may be a potential target of therapy.Key words: Langerhans cell histiocytosis - mutations - prognostic factors - relapse - survival.