Long-term response with the atypical reaction to nivolumab in microsatellite stability metastatic colorectal cancer: A case report.

Immunotherapy has become an integral part of a comprehensive treatment approach to metastatic colorectal cancer (mCRC). Nivolumab (Opdivo) is a human immunoglobulin G4 monoclonal antibody that blocks the interaction between the programmed cell death 1 (PD-1) receptor and its ligands 1/2 (PD-L1/PD-L2), leading to inhibition of T-cell proliferation, cytokine secretion, and enhanced immune response. The US Food and Drug Administration (FDA) has approved this drug for use in high microsatellite instability (MSI-high)/deficiencies in mismatch repair (dMMR) advanced CRC patients. However, its efficacy is extremely limited in microsatellite stability (MSS)/mismatch repair proficient (pMMR) patients. We report a case of a 42-year-old man diagnosed with MSS/pMMR mCRC who has achieved a durable response to nivolumab after a progression under chemotherapy with antiangiogenic treatment. We observed for the first time an atypical response after 8 months of nivolumab treatment, with the regression of previous primary pulmonary lesions and the presence of new para-aortic lymph node lesions. This report demonstrates that a subset of pretreated mCRC patients with the MSS/pMMR phenotype may benefit from nivolumab and these patients need more attention.

Pathogenicity Reclassification of Genetic Variants Related to Early-Onset Breast Cancer among Women of Mongoloid Origin.

BACKGROUND: Germline alterations in BRCA1, BRCA2, and other genes are responsible for early-onset breast cancer. However, up to 20% of molecular tests report genetic variant of unknown significance (VUS) or novel variants that have never been previously described and their clinical significance are unknown. This study aimed to reclassify variant of unknown significance (VUS) or novel variants by using the ActiveDriveDB database that annotates variants through the lens of sites of post-translational modifications (PTM). METHODS: Our study included thirty-eighth young Buryat BC patients, belonging to the Mongoloid race and anthropologically to the Central Asia. Genomic DNA was extracted from the peripheral blood lymphocytes using the phenol/chloroform method. DNA library were prepared using the Hereditary Cancer SolutionTM kit (Sophia GENETICS, Switzerland) to cover 27 genes, such as ATM, APC, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, FAM175A, MLH1, MRE11A, MSH2, MSH6, MUTYH, NBN, PALB2, PIK3CA, PMS2, PMS2CL, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53, and XRCC2. Paired-end sequencing (2 x 150 bp) was conducted using NextSeq 500 system (Illumina, USA). RESULTS: We re-examined 135 rare variants (41 VUS, 25 conflicting, 64 benign and 5 new variants). We identified 10 out of 135 (7.4%) mutations that affected the sites of post-translational modification in proteins. Of 135 rare mutations, 1 benign variant was reclassified as network-rewiring - motif loss mutation, 3 VUS and 1 new variant were reclassified as distal PTM- mutations, 2 new and 1 benign variant were classified as proximal PTM- mutations and 1 benign and 1 conflicting variant were classified as direct PTM- mutations. CONCLUSIONS: For the first time, 7.4% (10 out of 135) of mutations that affected the sites of post-translational modification in proteins were identified among early-onset breast cancer women of Mongoloid origin.

Role of TGF-ß signaling in the mechanisms of tamoxifen resistance.

The transforming growth factor beta (TGF-ß) signaling pathway plays complex role in the regulation of cell proliferation, apoptosis and differentiation in breast cancer. TGF-ß activation can lead to multiple cellular responses mediating the drug resistance evolution, including the resistance to antiestrogens. Tamoxifen is the most commonly prescribed antiestrogen that functionally involved in regulation of TGF-ß activity. In this review, we focus on the role of TGF-ß signaling in the mechanisms of tamoxifen resistance, including its interaction with estrogen receptors alfa (ERα) pathway and breast cancer stem cells (BCSCs). We summarize the current reported data regarding TGF-ß signaling components as markers of tamoxifen resistance and review current approaches to overcoming tamoxifen resistance based on studies of TGF-ß signaling.

New germline mutations in non-BRCA genes among breast cancer women of Mongoloid origin.

In accordance with the Asian BRCA Consortium data, there is a significant difference in incidence rate of breast cancer depending on age, as well as spectrum and prevalence of BRCA1/2 mutations between Mongoloid (East Asian) and Caucasoid (European) people. However, European strategies to identify familial BC are still applied to the Asian population, including Russian Mongoloids (Khakas, Buryats, Tyvans and Yakuts and others). The main purpose of the study was to identify molecular changes associated with hereditary BC in Russian Mongoloid BC patients (Buryats). Thirty-nine patients were included in the study. Genomic DNA extracted from lymphocytes was used to prepare DNA-libraries. Target sequencing was designed to cover 27 genes, such as ATM, APC, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2 and others. Paired-end sequencing (2 × 150 bp) was conducted on a NextSeq 500 system (Illumina, USA). Three pathogenic mutations in non-BRCA genes were found (prevalence of 8%). The pathogenic mutations were found in the RAD51D and PTEN genes. The pathogenic variant in the RAD51D gene (rs137886232, NC_000017.10:g.33428366G>A, p.R141X) was observed in two unrelated individuals aged under 40. One of these patients had a family history of late-onset stomach cancer in second-degree relatives. The pathogenic mutation in the PTEN gene (rs786201044, NC_000010.10:g.89692922T>C, p.C136R) was observed in a 38 years old breast cancer patient with no family history. In our study, we first describe pathogenic mutations in RAD51D and PTEN genes found in young Buryat patients.

Impact of estrogen receptor α on the tamoxifen response and prognosis in luminal-A-like and luminal-B-like breast cancer.

The luminal-A-like and luminal-B-like breast cancer groups have distinct biological features that lead to differences in the treatment response and clinical outcome. The aim of this study was to examine the value of the distribution pattern of ERα expression, ESR1 SNPs as well as ESR1 mRNA expression in predicting tamoxifen response and survival in patients with luminal-A-like and luminal-B-like breast cancer. A total of 135 patients with both subtypes were stratified into two groups depending on the tamoxifen response: tamoxifen-resistant patients (TR) and tamoxifen-sensitive patients (TS). ESR1 mRNA expression was measured by real-time quantitative reverse transcription-PCR. Three polymorphisms of ESR1 (rs2077647, rs2228480 and rs1801132) were genotyped using a TaqMan assay. The distribution pattern of ERα expression was analyzed immunohistochemically using the visual assessment of staining. The primary endpoint was progression-free survival (PFS). There was a significant decrease in ESR1 mRNA expression level in the TR group when compared to the TS group among patients with luminal-B-like subtype (P = 0.038). ESR1 2014AA mutant genotype of rs2228480 was more prevalent in the TR patients with luminal-B-like subtype than the TS group (P = 0.045). In the luminal-A-like group, tamoxifen-resistant tumors were more frequently heterogeneous for ERα expression than tamoxifen-sensitive tumors (P = 0.016). Multivariate analysis showed a strong association of lymph node status and the distribution pattern of ERα expression with tamoxifen responsiveness in this cohort of patients. In addition, a luminal-A-like patients with the heterogeneous ERα expression had a significantly shorter PFS time than those with the homogeneous ERα (P = 0.013). These results indicate that the heterogeneous expression of ERα is an accurate predictor of tamoxifen response and survival in luminal-A-like breast cancer patients. ESR1 rs2228480 may act as a marker with a high prognostic potential in luminal-B-like tumors.

Predictive value of vascular endothelial growth factor receptor type 2 in triple-negative breast cancer patients treated with neoadjuvant chemotherapy.

The identification of informative biomarkers that could predict the treatment response is particularly important in the triple-negative (TN) breast cancer, which is characterized by biological diversity. The aim of this study was to investigate the impact of vascular endothelial growth factor receptor (VEGFR2) expression and its gene polymorphisms on pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) in Russian patients with TN breast cancer. We performed a retrospective analysis of 70 women with operable TN breast cancer, who underwent NCT with 5-fluorouracil, adriamycin, and cyclophosphamide (FAC) or cyclophosphamide, adriamycin, and capecitabine (CAX) between 2007 and 2013. VEGFR2 expression was evaluated before NCT by immunohistochemistry. TaqMan SNP assays were used for genotyping KDR - 604T>C (rs2071559) and KDR 1192G>A (rs2305948) polymorphisms. The pCR was used as an end-point in the treatment efficacy analysis. In the univariate analysis, the pCR rate was strongly associated with young age (P = 0.004), high Ki67 expression (P = 0.012), lymph node negativity (P = 0.023) as well as with positive VEGFR2 expression (P = 0.019) and the CAX regimen (P = 0.005). In the multivariate analysis, only patient's age (P = 0.005) and pre-NCT VEGFR2 expression (P = 0.048) remained significant predictors of pCR. The pCR rate was higher in the CAX-treated patients than that in the FAC-treated patients (P = 0.005). Our results revealed that - 604TT genotype of rs2071559 and age < 50 years were correlated with a pCR in the CAX-treated patients. VEGFR2 expression in pre-NCT tumors and KDR gene polymorphism can be considered as additional predictive molecular markers of pCR in Russian TN breast cancer patients treated with NCT.

The distribution pattern of ERα expression, ESR1 genetic variation and expression of growth factor receptors: association with breast cancer prognosis in Russian patients treated with adjuvant tamoxifen.

Identification of additional biomarkers associated with ER genomic and nongenomic pathways could be very useful to distinguish patients who will benefit from tamoxifen treatment. The aim of this study was to analyze the prognostic significance of the distribution pattern of ERα expression, ESR1 gene single-nucleotide polymorphisms and expression levels of growth factor receptors in Russian hormone receptor-positive breast cancer patients treated with adjuvant tamoxifen. Formalin-fixed paraffin-embedded tumor tissue samples from 97 patients were examined for the distribution pattern of ERα expression, as well as for EGFR and TGF-ßR1 expression by immunohistochemistry. Genotypes for ESR1 +30T>C (rs2077647) and ESR1 2014G>A (rs2228480) were analyzed using a TaqMan assay. Progression-free survival (PFS) was used as an endpoint for the survival analyses. We found that patients with the heterogeneous distribution of ERα expression had poor prognosis on tamoxifen treatment (P = 0.021). We identified a high EGFR expression in patients who developed distant metastasis or recurrence during tamoxifen treatment (a tamoxifen-resistant group-TR) in contrast to the distant metastasis-free patients (a tamoxifen-sensitive group-TS) (80.0 vs. 41.9 %, respectively, P = 0.009). Carriers of the ESR12014A mutant allele were more prevalent among the TR patients compared to the TS patients (26.3 vs. 8.0 %, respectively, P = 0.009). EGFR expression and the distribution pattern of ERα expression were associated with the response to tamoxifen by both univariate and multivariate logistic regression analyses. The presence of these markers either alone or in combination was correlated with the worse PFS for all patients. Analysis of the distribution pattern of ERα expression and the EGFR status in tumor tissue may be valuable for patient selection for tamoxifen adjuvant therapy.

Neoadjuvant chemotherapy for different molecular breast cancer subtypes: a retrospective study in Russian population.

The aim of this retrospective study was to evaluate the objective clinical response (cOR), pathological complete response (pCR), and progression-free survival (PFS) in 231 Russian patients with four subtypes of breast cancer treated with neoadjuvant chemotherapy. About 130 (56.3 %) patients received anthracycline-based, 56 (24.2 %) capecitabine-containing (CAX), 28 (12.1 %) taxotere and 17 (7.4 %) non-anthracycline-containing chemotherapy regimens at the Tomsk Cancer Research Institute between 2000 and 2010. Tumors were subtyped according to the hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) immunohistochemical data. The majority of tumors (48.9 %) were ER+/PR+ and HER2-negative (HR+/HER2-), 10.4 % were ER+ PR+ and HER2-positive (HR+/HER2+), 9.1 % were ER-/PR- and HER2-overexpressed (HER2-enriched) and 31.6 % were ER-/PR- and HER2-negative (triple negative). Both cOR and pCR were significantly higher in the triple-negative tumors compared to the other subtypes (P = 0.021 and P = 0.033, respectively). Among the four chemotherapy regimens, only CAX regimen had a predictive value for cOR (HR 2.30, 95 % CI 1.16-4.58, P = 0.009). Multivariate regression analysis showed that the triple-negative subtype (HR 2.54, 95 % CI 1.06-1.42, P = 0.011) and CAX regimen (HR 3.01, 95 % CI 1.01-1.46, P = 0.002) were significantly associated with cOR. No association between patient's PFS and a tumor subtype was observed. However, there was a trend for a prolonged PFS among patients with cOR (P = 0.056). Our data indicate a potentially better prognosis for triple-negative breast cancer patients if treated with the CAX neoadjuvant regimen.

The effect of folate-related SNPs on clinicopathological features, response to neoadjuvant treatment and survival in pre- and postmenopausal breast cancer patients.

This study aimed to investigate the relationship of ten single nucleotide polymorphisms (SNPs) in the MTHFR, MTR, MTRR, DHFR, MTHFD1, TS, RFC1 and DNMT3b genes with cancer survival, therapeutic response to neoadjuvant chemotherapy and clinicopathological characteristics in 300 pre- and postmenopausal breast cancer patients of a Russian Western Siberian population. We found that the MTHFR 677CT genotype as well as combination of MTHFR 677CT and 677TT genotype was related to tumor size and estrogen-positive status in postmenopausal group. The RFC1 80А allele was associated with an increased risk of lymph node metastases among postmenopausal women. The MTHFR 677TT genotype was significantly correlated with a better progression-free survival in premenopausal patients. In contrast, a worse outcome was observed in this group patient with MTHFD1 1958AA genotype. In the multivariate analysis, the MTHFD1 1958AA genotype was identified as an independent prognostic factor for premenopausal breast cancer survival. Our findings provide evidence for associations of breast cancer survival with folate-related SNPs in a population of Western Siberian region of Russia and the MTHFD1 (1958G>A) may have additional prognostic value especially among premenopausal patients.

Association of functional -509C>T polymorphism in the TGF-ß1 gene with infiltrating ductal breast carcinoma risk in a Russian Western Siberian population.

BACKGROUND: Transforming growth factor ß1 (TGF-ß1) is a multifunctional cytokine that plays an important role in human mammary carcinogenesis. The purpose of this study was to investigate the association between -509C>T single nucleotide polymorphism (SNP) of the TGF-ß1 gene and infiltrating ductal breast carcinoma risk in Russian patients of Western Siberian region. MATERIALS AND METHODS: Blood samples collected from 218 women with histologically confirmed infiltrating ductal breast carcinoma and 290 healthy female controls were analyzed through polymerase chain reaction-restriction fragment length polymorphism methods. RESULTS: The -509TT genotype was significantly associated with a decreased risk for ductal breast carcinoma (OR=0.47, CI: 0.26-0.82, P=0.004). Similarly, the -509T was significantly less in ductal breast cancer patients (34.4%) than in control individuals (41.6%; OR=0.74, CI: 0.57-0.96, P=0.02). With the exception of association between the -509TT genotype and large tumor size (P=0.01), there was no significant association between the studied polymorphism and clinicopathological characteristics. CONCLUSION: The results of this study suggest that polymorphism of TGF-ß1 -509C>T gene may modify individual susceptibility to infiltrating ductal breast carcinoma in Russian women of Western Siberian region.