Renal Cell Carcinoma (RCC) and uterine
leiomyoma (often referred to as
fibroids) are
tumors arising from tubular epithelium and myometrial compartments of the kidney and uterus, respectively. These
tumors have a very different clinical presentation, with RCC being one of the less common
cancers, having a very poor prognosis, and occurring predominantly in men, whereas uterine
leiomyoma are the most common
tumor of women and are benign. Although they are distinct histologically, with RCC arising from epithelial cells and
leiomyoma arising from smooth muscle cells, they share a common embryological origin. Renal tubular epithelial cells arise during nephrogenesis as a result of the mesenchymal-epithelial transition of condensed mesenchyme induced by the developing ureteric bud, and have a shared mesenchymal lineage with smooth muscle cells of the uterus. In addition to a common embryological origin, RCC and
leiomyoma have been demonstrated to share a common genetic etiology. The Eker rat model was the first demonstration of a specific genetic linkage between RCC and uterine
leiomyoma. Eker rats carry a germline defect in the rat homologue of the
tuberous sclerosis complex 2 (TSC-2) tumor suppressor gene and develop spontaneous RCC and uterine
leiomyoma with a high frequency.
TSC patients are also at risk for RCC, and sporadic human uterine
leiomyomas exhibit loss of function of the TSC-2 gene product,
tuberin. Individuals with the inherited
cancer syndrome hereditary leiomyomatosis and
renal cell cancer (HLRCC) that have germline defects in the
fumarate hydratase (FH) gene develop papillary RCC and uterine and skin
leiomyomas. Benign cutaneous lesions and uterine
leiomyoma also arise in German Shepherd dogs with germline mutations in the Birt-Hogg-Dube (BHD) gene, and these animals develop RCC and uterine
leiomyoma with a high frequency. Identification of the tumor suppressor genes involved in these diseases,
TSC, FH and BHD, and the elucidation of the function of their
protein products,
tuberin,
fumarate hydratase and folliculin, respectively, opens new avenues for understanding the pathogenesis of both RCC and uterine
leiomyoma.