Sex Differences in the Predictive Power of the Molecular Prognostic Factor HER2/neu in Patients with Non–Small-Cell Lung Cancer

BackgroundRecent studies imply that HER2/neu is a potential prognostic factor in patients with non–smallcell lung cancer (NSCLC). Whereas considerable evidence indicates sex differences in epidemiologic, hormonal, biologic, and genetic factors in this disease, it has remained unknown whether HER2/neu has a diverse function as a prognostic factor in men and women.Patients and MethodsWe investigated the association between gene expression levels of HER2/neu in the primary tumors of 90 patients with curable resected NSCLC and survival, especially analyzing whether there is a different potential of this molecular factor in its prognostic impact between men and women.ResultsHigh HER2/neu gene expression levels were found in 62 patients (68.9%), and low HER2/neu gene expression levels were found in 28 patients (31.1%). High HER2/neu messenger RNA expression levels were associated with inferior survival (P = 0.09) compared with lower HER2/neu expression. Survival analysis was then carried out separately for men and women in this group of patients. An HER2/neu gene expression cutoff point was identified that separated women, but not men, into good and poor prognostic groups.ConclusionThese findings suggest that HER2/neu as a prognostic factor is strongly sex specific, indicating that it is not useful for men but highly predictive for women.