Microbiota as the unifying factor behind the hallmarks of cancer

The human microbiota is a complex ecosystem that colonizes body surfaces and interacts with host organ systems, especially the immune system. Since the composition of this ecosystem depends on a variety of internal and external factors, each individual harbors a unique set of microbes. These differences in microbiota composition make individuals either more or less susceptible to various diseases, including cancer. Specific microbes are associated with cancer etiology and pathogenesis and several mechanisms of how they drive the typical hallmarks of cancer were recently identified. Although most microbes reside in the distal gut, they can influence cancer initiation and progression in distant tissues, as well as modulate the outcomes of established cancer therapies. Here, we describe the mechanisms by which microbes influence carcinogenesis and discuss their current and potential future applications in cancer diagnostics and management.

Radiation-Induced Lymphopoenia and Treatment Outcome in Hereditary Breast Cancer Patients

Many breast cancer (BC) predisposition genes encode proteins involved in DNA damage repair (DDR). Identification of germline pathogenic va-riants (PV) in DDR genes raises the question whether their presence can influence the treatment outcomes and potential radiation-induced toxicity in their carriers treated by adjuvant radiotherapy, which has not yet been answered conclusively. We retrospectively examined records of 213 BC patients treated by adjuvant radiotherapy, including 39 (18.3 %) BRCA1/2 PV carriers, 25 carriers (11.7 %) of PV in other breast cancer-predisposing genes, and 149 (70 %) non-carriers. Our goal was to examine 5-year disease-free survival (5y DFS) rates among the study groups and determine the impact of radiotherapy-induced lymphopoenia (RIL) on this outcome. While we found no significant difference in 5y DFS between non-carriers and carriers of BRCA mutations (86.4 % vs 78.4 % P = 0.24) or between non-carriers and other studied mutations (86.4 % vs 93.3 %; P = 0.27), respectively, we observed that the entire group of PV carriers had a significantly lower proportion of patients without RIL (P = 0.04) than the non-carriers. In contrast, subsequent analyses indicated a non-significant trend toward an increased 5y DFS in PV carriers with RIL. Our single-centre study indicated that the presence of PV in BC patients has an insignificant impact on DFS but can reduce the risk of RIL associated with adjuvant radiotherapy. It remains unclear whether this may result from the paradoxical activation of anti-tumour immunity in PV carriers with higher lymphocyte consumption resulting from higher immune effectiveness.

New methodology of TMB assessment from tissue and liquid biopsy in NSCLC

Immunotherapy has dramatically influenced and changed therapeutical approach in non-small cell lung cancer (NSCLC) in recent five years. Even though we can reach long-term response to this treatment in approximately 20% of patients with NSCLC, we are still not able to identify this cohort of patients based on predictive biomarkers. In our study we have focused on tumor mutation burden (TMB), one of the potential biomarkers which could predict effectiveness of check-point inhibitors, but has several limitations, especially in multiple approaches to TMB quantification and ununiform threshold. We determined the value of TMB in tumor tissue (tTMB) and blood (bTMB) in 20 patients with early stage NSCLC using original custom gene panel LMB_TMB1. We evaluated various possibilities of TMB calculation and concluded that TMB should be counted from both somatic non-synonymous and synonymous mutations. Considering various factors, we established cut-offs of tTMB in/excluding HLA genes as ≥22 mut/Mb and 12 mut/Mb respectively, and cut-offs of bTMB were defined as ≥21 mut/Mb and ≥5 mut/Mb, respectively. We also observed trend in correlation of somatic mutations in HLA genes with overall survival of patients.