Microsatellite instability (MSI) is a marker of the replication error phenotype. It is caused by impaired DNA mismatch repair processes (MMR), resulting in ineffectiveness of the mechanisms responsible for the DNA replication precision and postreplicative DNA repair. MSI underlies the pathogenesis of 10%–20% of colorectal cancer (CRC) cases. The data about the potential value of MMR status as a predictive factor for 5-fluorouracil (FU)-based chemotherapy remain unclear. According to National Comprehensive Cancer Network updated guidelines, MSI testing is recommended for all patients with stage II CRC because patients with MSI-H (high-frequency MSI) tumour may have a good prognosis and obtain no benefit from 5-FU-based adjuvant chemotherapy. The significance of the MSI status as a predictive factor for patients with metastatic disease was not confirmed. The association between the MSI status and the efficacy of the therapy based on anti-programmed death-1 receptor inhibitors requires further studies.

Oxidative stress may play an important role in colorectal cancer (CRC). The present study included 94 adult patients with CRC (52 men and 42 women) and 26 hospitalized patients (12 men and 14 women) in whom CRC was excluded (control group). During hospitalization, blood serum samples were collected from both groups. Apart from that, anthropometric measurements were taken and other clinical data were analyzed. Serum malondialdehyde (MDA) level, total oxidant status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI) were assayed. Subsequently, the relationship between the analyzed oxidative stress markers and selected clinical characteristics was investigated in both groups. The evaluation of oxidative stress marker values demonstrated that MDA and TAS levels were significantly higher in the control group than the CRC group (p < 0.001 and p = 0.019, respectively), while TOS levels were significantly higher in the CRC group than the control group (p = 0.005). Significantly lower OSI levels were found in the control group than in the CRC group (p < 0.001). Similar results can be observed when performing ROC analysis (receiver operating characteristic curve). Preliminary statistical analysis demonstrated that MDA levels in the study group depend on the location of the primary tumour (p = 0.035). Based on the post hoc Tukey test, a relationship was demonstrated between the MDA level and the left and right side of the colon (p = 0.040). The results may be evidence for a higher level of oxidative stress, including a compromised antioxidative defence system, in patients with CRC.

Background and objectives: Ample evidence indicates that oxidative stress, including complex lipid peroxidation processes, may play a significant role in the pathogenesis of colorectal cancer. The goal of this study was to evaluate selected oxidative stress markers in patients with colorectal cancer depending on some clinical features, with particular attention paid to the location of the primary tumor. Materials and Methods: The study was conducted on a group of 66 patients with colorectal cancer. The study consisted of two stages. The first stage involved the analysis of medical records; the second consisted of determining selected oxidative stress markers by measuring malondialdehyde as well as total oxidant and antioxidant status. Results: Of all patients, 43 (65.15%) had colon cancer, of whom 30 (69.77%) had a tumor on the left side and 13 (30.23%) had a tumor on the right side of the colon. Of all the patients, 23 (34.85%) had rectal cancer. The mean total oxidant and antioxidant status was 809.76 (SD ± 392.65) µmol/L and 253.19 (233.33–310.66) µmol/L, respectively. The mean malondialdehyde serum level was 2478.04 (SD ± 1397.05) ng/mL. The mean malondialdehyde serum concentration in patients with primary tumors located on the right side was higher in a statistically significant way compared with the remaining patients. Conclusions: It was demonstrated that the intensity of lipid peroxidation processes is correlated with the development of colorectal cancer, particularly on the right side. The results should be interpreted rather cautiously due to certain limitations of the study.

Mounting evidence suggests that inflammation, immune response, and coagulation status determine many processes during the carcinogenesis pathway in colorectal cancer (CRC). Inflammation strongly promotes tumor formation, progression, and metastasis. The systemic inflammatory response (SIR) may be reflected by simple indicators evaluated on the basis of peripheral blood morphology parameters. The indices are easily obtained by the peripheral blood test and could be promising biomarkers for CRC. We present the results of the retrospective study evaluating the potential relation between the platelet indices (platelet count (PC), platelet-to-lymphocyte ratio (PLR), neutrophil platelet score (NPS), mean platelet volume (MPV), and MPV/PC ratio) and the clinicopathological features of CRC patients. The study included 247 patients (104 males and 143 females) aged 39-87 years with CRC stages II-IV. The complete blood counts with the automated differential counts were performed prior to the qualification to systemic treatment. High PC, high PLR, and NPS 0 were associated with older age and higher BMI of the patients. No link between the analyzed platelet indices and histological grade of the tumor, primary tumor location, and gender was noted. The patients aged ≥65 years were characterized by the higher MPV/PC ratio than the younger population. We observed a trend to the higher MPV/PC ratio among the patients with excessive body weight defined by BMI compared to BMI within normal limits. A higher frequency of PC>400, NPS 1 and 2, and a trend to more frequent PLR≥150 were observed in the subgroup with metastatic disease compared to individuals with CRC stages II and III. The presented results expand the knowledge on potential association between SIR parameters and other clinicopathological factors that should be considered during interpreting the prognostic and predictive value of the inflammation parameters.

Colorectal cancer is one of the most common cancers in the world. Due to its still undetermined pathogenesis, we are searching for signaling pathways that are important in the development of colorectal cancer. In this article, we present results of study on the role of ADAM proteins in colorectal cancer. The study included 85 adult colorectal cancer patients (48 men, 37 women) and 25 patients in the control group (after diagnostic colonoscopy—without cancer). During hospitalization, a serum sample (3 cm³) was collected from the study and control group, anthropometric measurements were conducted and others clinical data were analyzed. In the serum ADAM10, 12, 17, and 28, protein concentrations were determined and, in the next step, examined the relationship between ADAMs concentrations and selected clinical parameters in both groups. The analysis showed that serum levels of ADAM10 and ADAM28 are significantly higher in patients with colorectal cancer and correlate with histopathological grading and with presence of distant metastases. Moreover, noticed the trend to correlate concentrations of adamalysines with higher BMI score. One of the functions of adamalysines is the activation of growth factors involved in cancer, including IGF and TNFα. The increased activity of adamalysines in patients may play a role in the pathogenesis of colorectal cancer. Our study highlights the prevalence of metabolic disorders in the group of patients with diagnosed CRC, and this cancer seems to be a further complication of obesity.