İlhan Hacıbekiroğlu

Aim: To compare the seropositivity rate of cancer patients with noncancer controls after inactive SARS-CoV-2 vaccination and evaluate the factors affecting seropositivity. Method: Spike IgG antibodies against SARS-CoV-2 were measured in blood samples of 776 cancer patients and 715 noncancer volunteers. An IgG level ≥50 AU/ml is accepted as seropositive. Results: The seropositivity rate was 85.2% in the patient group and 97.5% in the control group. The seropositivity rate and antibody levels were significantly lower in the patient group (p < 0.001). Age and chemotherapy were associated with lower seropositivity in cancer patients (p < 0.001). Conclusion: This study highlighted the efficacy and safety of the inactivated vaccine in cancer patients. Clinical Trials Registration: NCT04771559 (ClinicalTrials.gov)

PURPOSE: To investigate clinicopathological features in patients with recurrent colorectal cancer within 1 year and more than 1 year after curative resection. MATERIALS AND METHODS: We retrospectively evaluated 103 patients with disease recurrence before versus after 1 year of resection. Thirty-two patients (31%) were diagnosed with recurrence less than 1 year after curative resection for colorectal cancer (early recurrence) and 71 (69%) after more than 1 year (non-early recurrence). RESULTS: The early recurrence group displayed a significantly lower overall survival rate for both colon cancer (p=0, 01) and rectal cancer (p<0.001). Inadequate lymph node dissection was a significant predictor for early relapse. There were no statistically significant differences in clinicopathological variables such as age, sex, primary tumor localization, stage, depth of invasion, lymphovascular invasion and perineural invasion between the early and non-early recurrence groups. However, a K-ras mutation subgroup was significantly associated with early recurrence (p<0.001). CONCLUSIONS: Poor survival is associated with early recurrence for patients undergoing resection for non-metastatic colorectal cancer, as well as K-ras mutation.

Testicular cancer is a relatively rare tumor type, accounting for approximately 1% of all cancers in men. However, among men aged between 15 and 40 years, testicular cancer is the most commonly diagnosed malignancy. Testicular germ cell tumors (TGCTs) are classified as seminoma and non-seminoma. The RAS oncogene controls several cellular functions, including cell proliferation, apoptosis, migration, and differentiation. Thus, RAS signaling is important for normal germ cell development. Mutations of the Kirsten RAS (K-RAS) gene are present in over 20% of all cancers. RAS gene mutations have also been reported in TGCTs. We investigated K-RAS and N-RAS mutations in seminoma and non-seminoma TGCT patients. A total of 24 (55%) pure seminoma cases and 19 (45%) non-seminoma cases were included in the study. K-RAS and N-RAS analyses were performed in our molecular pathology laboratory, using K-RAS and N-RAS Pyro Kit 24 V1 (Qiagen). In total, a RAS mutation was present in 12 patients (27%): 7 seminoma (29%) and 5 non-seminoma cases (26%) [p = 0.55]. A K-RAS mutation was present in 4 pure seminoma tumors (16%) and 3 non-seminoma tumors (15%) [p = 0.63], and an N-RAS mutation was observed in 4 seminoma tumors (16%) and 3 non-seminoma tumors (15%) [p = 0.63]. Both, K-RAS and N-RAS mutations were present in two patients: one with seminoma tumor and the other with non-seminoma tumor. To date, no approved targeted therapy is available for the treatment of TGCTs. The analysis of K-RAS and N-RAS mutations in these tumors may provide more treatment options, especially in platinum-resistant tumors.

The aim of this study was to investigate the clinicopathological characteristics and distribution by tumor localization of KRAS point mutations in metastatic colorectal cancer. A total of 189 patients diagnosed with colorectal cancer between 2007 and 2014, who were either metastatic at the time of diagnosis or developed metastasis subsequently, were included in this study. KRAS mutation analysis was performed in the primary tumor tissues and KRAS mutations were identified in 47.6% of the patients. There was a high frequency of the p.G13D point mutation in left-colon tumors (P=0.011), while the p.G12D point mutation was more frequent in right-colon tumors (P=0.004). KRAS wild-type frequency (P=0.02) was higher among patients aged <40 years. A comparison of codon 12 and 13 mutations revealed that codon 12 mutations were more common in the >50-year-old group (P=0.03) and codon 13 mutations were more common in the <70-year-old group (P=0.04). KRAS wild-type tumors were localized in the right colon (P=0.005) and tumors with the p.G13D point mutation (P=0.018) were diagnosed at non-metastatic stages. In conclusion, KRAS point mutations in colorectal cancer exhibited a heterogeneous distribution in terms of tumor localization. In addition, the p.G13D point mutation was found to differ from other mutations in several aspects.