PCR-based detection of EGFR, ALK, KRAS and BRAF mutations in Russian patients with lung adenocarcinoma: a single-center experience.

In contrast to other countries with predominantly white populations, Russian smoking-related lung cancers (LC) are mainly squamous cell carcinomas and approximately half lung adenocarcinomas (AdCa) are not related to tobacco consumption. Given that smoking significantly influences the probability of presence of actionable mutations in LC, one would expect that Russian lung AdCa patients would differ from other white populations in distribution of EGFR, ALK, KRAS and BRAF mutations. Herein, 2,336 consecutive lung AdCa cases, including 1,203 patients with known smoking status, were subjected to sequential testing for the above mutations. One quarter of lung AdCa patients carried either EGFR or ALK mutation with combined prevalence of 42% in those who had never smoked but only 8% in smokers. There was only a moderate difference in KRAS mutation frequency between ever- and never-smokers in EGFR/ALK-negative cases (31% vs. 23%), and this was mainly attributed to increased prevalence of G12C substitution in the former group. The occurrence of BRAF V600E mutation was 1.7% and 4% in EGFR/ALK/KRAS mutation-negative ever- and never-smokers, respectively. ALK testing of 470 EGFR-mutated tumors revealed only 1 (0.2%) instance of translocation. Similarly, KRAS testing identified 1 (1.25%) mutation in 80 EGFR-mutated AdCa and none in 48 ALK-rearranged AdCa. Therefore, concurrent actionable mutations in lung adenocarcinoma are exceptionally rare and sequential gene testing can be regarded as a reliable option.

Spectrum of APC and MUTYH germ-line mutations in Russian patients with colorectal malignancies.

Distribution of cancer-predisposing mutations demonstrates significant interethnic variations. This study aimed to evaluate patterns of APC and MUTYH germ-line mutations in Russian patients with colorectal malignancies. APC gene defects were identified in 26/38 (68%) subjects with colon polyposis; 8/26 (31%) APC mutations were associated with 2 known mutational hotspots (p.E1309Dfs*4 [n = 5] and p.Q1062fs* [n = 3]), while 6/26 (23%) mutations were novel (p.K73Nfs*6, p.S254Hfs*12, p.S1072Kfs*9, p.E1547Kfs*11, p.L1564X and p.C1263Wfs*22). Biallelic mutations in MUTYH gene were detected in 3/12 (25%) remaining subjects with polyposis and in 6/90 (6.7%) patients with colorectal cancer (CRC) carrying KRAS p.G12C substitution, but not in 231 early-onset CRC cases negative for KRAS p.G12C allele. In addition to known European founder alleles p.Y179C and p.G396D, this study revealed a recurrent character of MUTYH p.R245H germ-line mutation. Besides that, 3 novel pathogenic MUTYH alleles (p.L111P, p.R245S and p.Q293X) were found. Targeted next-generation sequencing of 7 APC/MUTYH mutation-negative DNA samples identified novel potentially pathogenic POLD1 variant (p.L460R) in 1 patient and known low-penetrant cancer-associated allele CHEK2 p.I157T in 3 patients. The analysis of 1120 healthy subjects revealed 15 heterozygous carriers of recurrent MUTYH mutations, thus the expected incidence of MUTYH-associated polyposis in Russia is likely to be 1:23 000.

[First Russian nationwide molecular epidemiological study for melanoma: results of BRAF mutation analysis].

This report presents the initial results of the first Russian molecular epidemiological study of melanoma. The investigation included 1035 patients with stage IIIB-IV melanoma residing in various regions of Russia. Sequencing of BRAF gene revealed mutation in 627 (60.6%) tumors; c.1799T > A (p.V600E) substitution was detected in 563 cases, and other mutations in 64 melanomas. Frequency of BRAF alterations was significantly higher in patients of younger age (< 50 years: 72.9%; > or = 50 years: 57.1%; p = 0.00003). 710 melanomas included in the study were located in sun non-exposed regions of the skin; this category of tumors was characterized by the highest occurrence of BRAF mutations (63.9%). In conclusion, more than a half of Russian patients with advanced melanoma are potential candidates for the treatment of kinase inhibitors of mutated BRAF.

[Pharmacoeconomic analysis of gefitinib therapy in patients with non-cell cell lung cancer].

We performed a treatment efficacy analysis for non-small cell lung cancer (NSCLC) patients' population with EGFR mutation aimed at optimization of pharmacoeconomic factors. The employment of gefitinib leads to an increase in patients' life expectancy for a median of 1.05 years. The average cost-effectiveness of this therapy is 934.8 thousand rubles per additional year (903.9-1100.5 thousand rubles for each year). If gefitinib therapy is given only to patients with proved EGFR mutation it can decrease the average expenses by 211.6-251.8 thousand rubles per patient in comparison to undiagnosed patients's population receiving gefitinib without a decrease in clinical effect. Comparison of selective gefitinib administration with isolated chemotherapy (CT) yields an incremental cost-effectiveness ratio of 960.7 to 1010.0 thousand rubles per additional year. Therefore, the strategy of EGFR gene mutations testing in patients with inoperable NSCLC with consequent gefitinib therapy administration in patients positive for mutation lead to an increase in life expectancy and is characterized by acceptable cost-effectiveness.

[Effectiveness of gefitinib (Iressa) as first-line therapy for inoperable non-small-cell lung cancer with mutated EGFR gene (phase II study)].

Tumor regression was reported in 20-30% of patients with inoperable non-small-cell lung cancer (NSLC) following standard first-line chemotherapy. Clinical trials with second-line gefitinib (Iressa) showed a strikingly high response in patients with mutated EGFR. However, clinical experience with gefitinib as first-line therapy had been limited to small-scale trials mostly among subjects of Asian origin. Our study was not associated with the drug manufacturer and included 25 chemotherapy-naive patients with mutated EGFR inoperable lung adenocarcinoma. Standard dose was 250 mg/day. Complete response was observed in 1 patient (4%), partial--11 (44%), sustained stabilization--13 (52%); median time until tumor progression--186 days. Median overall survival failed to be registered within the duration of the study. Among most frequent side-effects were skin rash (19; 76%) and diarrhea (14; 56%): marked side-effect -toxicity grade III (4; 16%). Gefitinib appeared highly efficient and tolerable and may be recommended as first-line treatment of mutated EGFR inoperable NSLC.

Hereditary breast-ovarian cancer syndrome in Russia.

Hereditary breast-ovarian cancer syndrome contributes to as much as 5-7% of breast cancer (BC) and 10-15% of ovarian cancer (OC) incidence. Mutations in the "canonical" genesBRCA1andBRCA2occur in 20-30% of affected pedigrees. In addition toBRCA1andBRCA2 mutations, germ-line lesions in theCHEK2,NBS1, andPALB2genes also contribute to familial BC clustering. The epidemiology of hereditary breast-ovarian cancer in Russia has some specific features. The impact of the "founder" effect is surprisingly remarkable: a single mutation,BRCA15382insC, accounts for the vast majority ofBRCA1defects across the country. In addition, there are two other recurrentBRCA1alleles:BRCA14153delA andBRCA1185delAG. BesidesBRCA1, in Russia breast cancer is often caused by germ-line alterations in theCHEK2andNBS1genes. In contrast toBRCA1andBRCA2, theCHEK2andNBS1heterozygosity does not significantly increase the OC risk. Several Russian breast cancer clinics recently started to investigate the efficacy of cisplatin in the therapy ofBRCA1-related cancers; initial results show a unique sensitivity ofBRCA1-associated tumours to this compound.