Association of Met-BDNF allele with pre-existing peripheral neuropathy in breast cancer patients.

Abstract

e21702 Background: We previously published preliminary results suggesting an association between the met-BDNF allele and vulnerability to paclitaxel-induced peripheral neuropathy (PIPN) in breast cancer patients. Here we present updated data obtained from our extended study. Methods: 35 patients; 34 women (33 with breast cancer and 1 with ovarian cancer) and one man (breast cancer) completed their follow-up. Peripheral neuropathy (PN) was assessed at diagnosis and along the treatment protocol, using the reduced version of Total Neuropathy Score (TNSr). Patients with TNSr≥2 at diagnosis were determined with pre-existing PN (Pre-PN). Allelic discrimination of BDNF polymorphism (rs6265) was determined by Sanger sequencing. Results: BDNF genotype Val/Val was found in 20 patients (57.14%), Val/Met in 15 patients (42.86%). No patient had the Met/Met genotype. 10 patients (28.57%) were diagnosed with Pre-PN, 3 of them with diabetic-related neuropathy. A higher incidences of the Met-BDNF allele was found in patients with Pre-PN as compared to patients with no Pre-PN (7/10 (70%) vs. 8/25 (32%) Val/Met in Pre-PN and no Pre-PN respectively, prob > ChiSq < 0.05). The three patients with diabetic related Pre-PN were genotyped Met-BDNF. The maximal TNSr scores developed by each patient during follow-up were higher in Met-BDNF patients compare to Val/Val patients. (Maximal TNSr mean ± SEM in Val/Val 4.80±0.62 vs. 7.73±1.34 in Val/Met BDNF, prob < t 0.04). No difference in the maximal TNSr scores between Met-BDNF and Val/Val patients were shown after excluding the patients with Pre-PN (Maximal TNSr mean ± SEM in Val/Val 5.05±0.78 vs. 5.25±0.62 in Val/Met BDNF, prob < t 0.44). Conclusions: Our data demonstrate an association between met-BDNF and Pre-PN. Higher maximal TNSr scores in our met-BDNF patients is generally the consequence of their higher Pre-PN.