Tumors and the heart: molecular genetic advances

Recent molecular genetic investigations of primary cardiac tumors (myxomas, lipomas, rhabdomyomas, and fibromas) have provided insight into fundamenta l mechanisms of cardiac cell growth. Myxomas are the most common adult card iac tumor, and familiar cardiac myxomas are now appreciated to be caused by mutations in the PRKAR1 alpha gene that encodes a regulatory subunit of pr otein kinase A. Cytogenetic studies have targeted candidate chromosomal loc i that may be perturbed during cardiac lipoma pathogenesis. Rhabdomyomas, t he most common pediatric cardiac neoplasm, are frequently associated with t uberous sclerosis, caused by mutations in the TSC-1 and TSC-P genes. The st udy of Gorlin syndrome has shed light on the etiology of cardiac fibromas. This disorder is caused by mutation of the PTC gene, which regulates cell g rowth, commitment and differentiation. In the future, manipulation of PRKAR 1 alpha-, TSC-, and PTC-dependent pathways may foster new strategies to reg enerate myocardium in the ischemic or myopathic heart. (C) 2001 Lippincott Williams & Wilkins, Inc.