A 56-year-old woman has had vaginal bleeding for 1 week. Her last menstrual period was 10 years ago. On physical examination, a lower abdominal mass is palpated. An endometrial biopsy is performed and shows endometrial carcinoma. An abdominal CT scan shows a 6-cm mass in the left ovary. A total abdominal hysterectomy is performed. Microscopically, the ovarian mass is a granulosa-theca cell tumor producing estrogen. Which of the following best describes the relationship between these two neoplasms?

Estrogen, similar to many other hormones and drugs, by itself is not carcinogenic, but it is responsible for the stimulation of endometrial growth (hyperplasia), which has a promoting effect when cellular mutations occur to produce carcinoma. Inherited susceptibility can never be completely excluded when an individual has two tumors; this can occur in patients with inherited mutations in the p53 gene. In this case, however, there is a clear hormonal basis for the second tumor. Faulty tumor suppressor genes are not involved in the hormonal promotion of a neoplasm. A paraneoplastic syndrome results from ectopic secretion of a hormone by the tumor (e.g., lung cancer cells producing corticotropin). Tumor heterogeneity does not refer to two separate kinds of neoplasms; it refers to heterogeneity with a given tumor or metastasis.