Background: Interindividual variability of pharmacogenetics may account for unpredictable neurotoxicities of taxanes. Methods: From March 2011 to June 2015, female patients with operable breast cancer who had received docetaxel- or paclitaxel-containing adjuvant chemotherapy were included in this study. All patients were treated with single-agent paclitaxel intravenously (IV) 175 mg/m² every 3 weeks for four cycles, or IV 80 mg/m² weekly for 12 cycles, and IV 100 mg/m² docetaxel for four cycles as adjuvant treatment. We evaluated the relationship between neurotoxicity of taxanes and single-nucleotide polymorphisms of ABCB1, CYP3A4, ERCC1, ERCC2, FGFR4, TP53, ERBB2, and CYP2C8 genes. Taxane-induced neurotoxicity during the treatment was evaluated according to the National Cancer Institute Common Toxicity Criteria version 4.03 prior to each cycle. Chi-squared tests were used to compare the two groups, and multivariate binary logistic regression models were used for determining possible risk factors of neuropathy. Results: Pharmacogenetic analysis was performed in 219 females. ABCB1 3435 TT genotype had significantly higher risk for grade ≥2 neurotoxicity (odds ratio [OR]: 2.759, 95% confidence interval [CI]: 1.172–6.493, P: 0.017) compared to TC and CC genotype, and also CYP3A4 392 AA and AG genotype had significantly higher risk for grade ≥2 neurotoxicity (OR: 2.259, 95% CI: 1.033–4.941, P: 0.038) compared to GG genotype. For FDGF4 gene with AG and GG genotype, OR was 1.879 (95% CI: 1.001–3.525, P: 0.048) compared to AA genotype with regard to any grade of neuropathy risk. We could not find any other association of other genotypes with neurotoxicity grades. Conclusion: ABCB1 3435 TT genotype and CYP3A4 392 AA/AG genotypes may be used as predictors of neurotoxicity during taxane chemotherapy.

The present study reports the case of a collision tumor consisting of follicular lymphoma (FL) and adenocarcinoma in the cecum of a 73-year-old man. To the best of our knowledge, the present study is the 11th case of a collision tumor consisting of colon adenocarcinoma and lymphoma to be reported in the literature, and the first case of cecum adenocarcinoma with low grade FL in the same segment of the cecum and the same regional lymph node to be reported. The present study reviewed the literature to determine treatment options for patients with collision tumors. The present patient was administered with adjuvant chemotherapy for T3N1M0 colon cancer following surgery, due to the dominance of colon adenocarcinoma in the collision tumor. Following the completion of treatment, progression of the untreated FL was observed. In the literature, patients with collision tumors are administered with chemotherapy for stage IV FL, and following the completion of treatment patients have presented with a recurrence of early stage colon adenocarcinoma. The recommended treatment for collision tumors is dependent on the dominant tumor; however, the treatment options for collision tumors in the literature appeared to exacerbate the other tumor. The characteristics of the tumors altered following chemotherapy, and immunological alterations in the tumors due to chemotherapy appear to have contributed to the exacerbation of the tumors. Therefore, patients with early‑stage tumors should be considered at risk of recurrence of other malignancies, which are present in collision tumors.