The DPYD * 2A variant statistically significantly associated with the specific AEs nausea/vomiting ( P = .007 ) and neutropenia ( P < .001 ) , whereas D949V statistically significantly associated with dehydration ( P = .02 ) , diarrhea ( P = .003 ) , leukopenia ( P = .002 ) , neutropenia ( P < .001 ) , and thrombocytopenia ( P < .001 ) .