Heterogeneity of excision repair cross-complementation group 1 gene expression in non-small-cell lung cancer patients.

Excision repair cross-complementation group 1 (ERCC1) gene expression analysis is currently used widely in the molecular diagnosis of cancer. According to numerous studies, ERCC1 gene expression correlates with overall survival and effectiveness of chemotherapy with platinum agents. However, the degree of this correlation differs among various studies, with certain authors reporting a complete lack of such a correlation. These contradictions may be attributed to a number of factors, including the heterogeneity of the tumor tissue. In this study, we attempted to assess the degree of genetic heterogeneity exhibited by tissue samples obtained from non-small-cell lung cancer (NSCLC) through the expression of the ERCC1 gene. This study included 25 samples of tumor tissue from patients with a morphologically confirmed NSCLC diagnosis. A total of three randomized sections of each specimen were used. The ERCC1 gene expression was assessed by quantitative polymerase chain reaction (qPCR) in the TaqMan format. When planning the experiment and analysis of qPCR data, the MIQE guidelines were taken into consideration. We established that the coefficient of variation of the relative level of ERCC1 gene expression in the majority of the samples exceeded 33% (P<0.05), indicating the significant heterogeneity of the sample. We also demonstrated that the degree of heterogeneity of the tumor tissue is largely dependent on disease stage.

Prevalence of human papillomaviruses in patients with head and neck squamous cell carcinoma in Lithuania and Belarus.

Overall, head and neck sqamous cell carcinoma accounts for more than 550,000 cases annually worldwide. It is well known that human papillomavirus (HPV) is the main risk factor for cervical cancer development. As the incidence and the mortality of cervical cancer are closely related to the HPV prevalence, we hypothesized that there is the same association between HPV prevalence and head and neck squamous cell carcinoma. Therefore we performed the study aiming to compare the level of HPV infection and HPV type distribution between two groups of Lithuanian and Belarusian patients with head and neck sqamous cell carcinoma. One hundred ninety head and neck sqamous cell carcinoma patients were included in the study, 75 from Lithuania and 115 from Belarus. PCR was used for HPV detection and typing. The distribution of HPV infection among head and neck sqamous cell carcinoma patients was similar in the Lithuanian (20.0%) and Belarusian (18.3%) patient groups, however differences were found in the distribution of HPV types.