Polymorphisms in CPT1B and CPT2 have no significant effect on plasma carnitine levels in Japanese cancer patients

Treatment of cancer patients undergoing chemotherapy with L-carnitine (LC) supplementation is becoming increasingly popular in the clinic. The present study aimed to examine the possible effects of polymorphisms in CPT1B and CPT2 (CPT1B G320D, S427C, c.282-18 C>T, and p.E531K, and CPT2 V368I) on the plasma concentration of carnitine in humans. The subjects were the 218 participants of the Iga Cohort Study. Differences in plasma-free carnitine levels by genotype were examined. Genotyping was conducted by polymerase chain reaction with confronting two-pair primers (PCR-CTPP). The plasma carnitine levels were significantly higher in males (P<0.001; Student’s t-test), and there was no significant difference in plasma carnitine levels between the age groups (P=0.202; ANOVA). One-way ANOVA revealed the plasma levels of carnitine were neither significantly different by CPT1B G320D, S427C, c.282-18 C>T, or p.E531K, nor by CPT2 V368I genotypes (P=0.133, P=0.538, P=0.636, P=0.509, and P=0.398, respectively). When analysis of covariance (ANCOVA) adjusted for age and sex was applied, the plasma levels of carnitine were not statistically significantly different according to these genotypes (P=0.299, P=0.715, P=0.980, P=0.851, and P=0.674, respectively). The present study did not identify any statistically significant differences in plasma carnitine levels between subjects with different CPT1 and CPT2 genotypes, suggesting that there may be no need to tailor treatments to patients’ genotypes when determining the dose/amount of LC to be administered to cancer patients undergoing palliative care.