Deletions in metastatic colorectal cancer with chromothripsis.

AIM: In our previously reported study, we found a correlation between DNA massive fragmentation and increased progression free survival (PFS) in metastatic colorectal cancer (mCRC), but not overall survival. The aim of this study is to find overlapping deleted genome regions in selected mCRC patients with chromothripsis and detect possible cause of increased PFS, and find new genes or combinations, involved in colorectal cancer oncogenesis. Materials and Methods: 10 mCRC patients with chromothripsis receiving 5-fluorouracil, oxaliplatin, leucovorin (FOLFOX) first-line palliative chemotherapy between August, 2011 and October, 2012 were selected for this study. Microarray analysis was performed using the Infinium HumanOmniExpress-12 v1.0 formalin-fixed paraffin-embedded (FFPE) BeadChip kit (Illumina). BeadChip was scaned on HiScan (Illumina). Analysis was performed by GenomeStudio software (Illumina) and R version 3.1.2. Copy number variation and breakpoints on the chromosomes were analyzed using the DNA copy package. RESULTS: Eight deleted tumor suppressor genes (ROBO2, CADM2, FAT4, PCDH10, PCDH18, CDH18, TSG1, CTNNA3) and four deleted oncogenes (CDH12, GPM6A, ADAM29, COL11A1) were identified in more than half of patients. In 70% patients' deletion in COL11A1 was detected. Deletion of MIR1269, MIR4465, MIR1261 and MIR4490 in patients with longer time to progression was observed. Four patients (40%) with PFS over 14 months, presented with NRG3 deletion (oncogene, еpidermal growth factor receptor (EGFR) ligand) what could possibly decrease proliferation of cancer cells via decreasing EGFR activation. CONCLUSIONS: Multiple chromosomal deletions (MIR1269, NRG3, ADK) in mCRC patients with chromothripsis are associated with better response to first line palliative FOLFOX-type chemotherapy and increased PFS.

Impact of KRAS variant rs61764370 on breast cancer morbidity.

UNLABELLED: Low-penetrance gene variants and their combinations are topical study objects in breast cancer pathogenesis. Single nucleotide polymorphism rs61764370, localized in 3՛ UTR of KRAS gene, plays an important role in the development and progression of several cancers. The aim of our study was to determine the KRAS variant impact on breast cancer morbidity. PATIENTS AND METHODS: 2214 patients diagnosed with breast cancer and 861 healthy controls were screened for KRAS variant by RFLP method. Available clinical data were collected and processed using statistical analysis methods. Results of present study suggest the KRAS variant impact on breast cancer development risk in premenopausal women, but it has no effect on breast cancer prognosis. We did not observe any KRAS variant effect on breast cancer patient 10-year disease-specific survival rates.

Survival rates of familial and sporadic prostate cancer patients.

AIM: To compare cancer-specific survival rates for familial and sporadic prostate cancer patients. MATERIALS AND METHODS: Gleason score and age at diagnosis of familial group and sporadic group were compared by χ(2) and t-test. Cancer-specific survival rates were analyzed by the Kaplan - Meier method and compared by log-rank test. Statistically significant level was set at p < 0.05. RESULTS: Among 1175 prostate cancer patients, familial group consisted of 215 (18.3%) patients, the sporadic group consisted of 960 (81.7%) patients. The familial group patient's mean age at diagnosis (58.9 years old, 95% confidence interval (CI) 57.8-60.1) was significantly younger than that of sporadic group patients (67.2 years old, 95% CI 66.7-67.6) (p < 0.0001). Comparing Gleason score between familial group and sporadic group revealed no statistically significant difference. The analysis showed that 92% (95% CI 0.88-0.97) of familial group patients had a 10-year cancer-specific survival rates, which was a significantly better outcome than that of sporadic group with 69% (95% CI 0.60-0.78) 10-year cancer-specific survival rates (p = 0.0237). CONCLUSION: The study data demonstrate statistically significant difference between familial group and sporadic group concerning age and cancer-specific survival rates, but not Gleason score.

The CHEK2 del5395 is a founder mutation without direct effects for cancer risk in the latvian population.

Our objective was to determine: 1) whether the checkpoint kinase 2 (CHEK2) del5395 (g.27417113-27422508 del, NC_000022.11) is a founder mutation in the Latvian population, 2) if there is an association between CHEK2 del5395 mutation and cancer risk, and 3) and whether the CHEK2 del5395 mutation impacts cancer predisposition in Chernobyl disaster liquidators (the civil and military personnel who were called upon to deal with consequences of the 1986 nuclear disaster) as well as geriatric populations. We recruited 438 breast cancer patients, 568 colorectal cancer patients, 399 ovarian cancer patients, 419 prostate cancer patients, 526 healthy blood donors, 480 Chernobyl disaster liquidators and 444 geriatric cancer-free participants. DNA samples were isolated from blood samples and subjected to multiplex polymerase chain reaction (PCR). The truncation of del5395 was estimated by fragment size of the multiplex PCR.All groups were compared to the healthy blood donors using Fisher's exact test. All p values were two-sided and the odds ratios (OR) calculated by two-by-two table. In cancer groups, the del5395 mutation was most frequently observed in the ovarian cancer group (1.00%, OR = 1.32). In control groups, the del5395 mutation was most frequent (0.76%) in the healthy donors, which exceeded its frequency in the Chernobyl liquidators group and the geriatric group by 0.01 and 0.08%, respectively. For all groups, the OR appeared to be >1 only in ovarian cancer patients. However, OR rates showed no statistical significance in either cancer or control groups, with the p value fluctuating within the range of 0.39-1.00. The CHEK2 gene del5395 is a founder mutation in the Latvian population, which, however, does not have a direct impact on genetic predisposition toward colorectal, breast, ovarian and prostate cancer.

Novel germline MLH1 and MSH2 mutations in Latvian Lynch syndrome families.

BACKGROUND/AIMS: Hereditary non-polyposis colorectal cancer or Lynch syndrome is an autosomal dominantly inherited disease with high penetrance, mostly due to mutations in the MLH1 and MSH2 genes. The aim of this study is to investigate the mutation spectrum of the MLH1 and MSH2 genes. METHODOLOGY: High risk colorectal cancer families were selected from overall 1053 consecutive patients. Screening of germline mutations in the MLH1 and MSH2 was performed by direct sequencing and multiplex ligation-dependent probe amplification. RESULTS: Ten patients fulfilled the Amsterdam I/II criteria and Bethesda guidelines of the Lynch syndrome. Three novel mutations were identified in MLH1 and MSH2 genes, as well as two known mutations in the MLH1 gene. Large rearrangements in the MLH1 gene were found in two patients. CONCLUSIONS: The mutations in the MLH1 and MSH2 genes in Latvian high-risk families are highly heterogeneous. Combination of direct sequencing and MLPA is the most appropriate molecular method of detecting hereditary nonpolyposis colorectal cancer patients and family members at risk.