CYP3A4 tumoral expression predicts therapy response and survival of PTCLu patients. Twenty-three patients with PTCLu were divided into 2 groups: those with CYP3A4 mRNA tumoral expression less than 2-fold the control sample content (low CYP3A4), and those with CYP3A4 mRNA greater than 2-fold the control sample content (high CYP3A4). (A) After the initial therapy, patients were classified as nonresponders (NR) or as having partial remission (PR) or complete remission (CR). The therapy response of the patient groups was compared by Pearson chi-square (P = .02) and Fisher exact (P = .041) tests. (B) Kaplan-Meier curves were constructed to analyze the survival of the 2 groups (P = .075).