Comprehensive Nursing Pharmacology Q 51
Estrogen antagonists are used to treat estrogen hormone-dependent cancer, such as breast carcinoma. Androgen antagonists block testosterone stimulation of androgen-dependent cancers. An example of an androgen-dependent cancer would be:
A. Prostate cancer.
B. Thyroid cancer.
C. Renal carcinoma.
D. Neuroblastoma.
Correct Answer: A. Prostate cancer
Prostate tissue is stimulated by androgens and suppressed by estrogens. Androgen antagonists will block testosterone stimulation of prostate carcinoma cells. The types of cancer in options 2-4 are not androgen-dependent. The prostate gland requires androgen (testosterone) to function optimally. This is why hormonal therapy (testosterone deprivation) is so effective. Castrate-resistant tumors are thought to generate intracellular androgens. Cancer begins with a mutation in normal prostate glandular cells, usually beginning with the peripheral basal cells. Prostate cancer is an adenocarcinoma as it develops primarily from the glandular part of the organ and shows typical glandular patterns on microscopic examination.
Option B: Thyroid cancer, as compared with other types of malignancies, is more closely associated with irradiation. Patients exposed during childhood have a much higher risk of developing thyroid carcinoma, and this risk is further compounded by higher doses of radiation, up to 1500 cGy due to thyroid cell killing at even higher dosages. As with other tumors, the role of oncogenes and tumor-suppressor genes in thyroid cancer cannot be overstated, and the transformation of a proto-oncogene to an oncogene or loss of a tumor suppressor gene is often the key step toward the initial malignant transformation. A point mutation in the BRAF gene is associated with up to 40% of cases of papillary thyroid cancer and is often associated with anaplastic thyroid cancer.
Option C: The most common type of cancer arising in the kidney is renal cell carcinoma (aka hypernephroma or Grawitz tumor), making up more than 9 out of 10 renal cancers in adults. Other types include transitional cell carcinomas of the renal pelvis, which behave like bladder cancers. Renal sarcoma is another rare tumor of the kidney. It is generally thought that renal cell carcinomas (RCCs) arise from the epithelial cells of the nephron, linking the CCRCC to the proximal tubular epithelium, PRCC to the distal tubular epithelium, and chromophobe RCC (ChRCC) to intercalated cells of the collecting duct. However, to the best of our literature search, reliable analysis is lacking. Based on the mice modeling study, it has been proposed that CCRCC may originate in the Bowman capsule.
Option D: Neuroblastoma (NB) is the most frequently occurring extracranial childhood tumor. It is classified as an embryonal neuroendocrine tumor, originating from neural crest progenitor cells. Hence, it can occur anywhere along with the sympathetic nervous system, including the superior cervical, paraspinal, and celiac ganglia; the majority arise in the adrenal glands. Many biological markers of neuroblastoma have been discovered, of which the most important is MYCN. This oncogene is overexpressed in nearly 25% of patients with neuroblastoma. The gene is also commonly found in patients with advanced cancer. Patients with the MYCN gene tend to have rapid progression of cancer and poor outcomes. On the other hand, expression of the H-Ras gene is associated with the low-stage disease.