To further investigate whether inactivation of the VHL tumor suppressor gene plays a role in tumorigenesis of MEN 2A-related MTC, we performed mutation analysis of the VHL gene and found mutations in at least 1 of the 7 C- cell specimens (Figs. 3 and 4, Table 1). The gene discussed is VHL; the disease is multiple endocrine neoplasia type 2A.