Germ cell tumor markers

NACB, National Academy of Clinical Biodiemistry ASCO, American Society of Clinical Oncology ACS, American Cancer Society EGTM, European Group on Tumor Markers tPSA, total PSA fPSA, free PSA NSGCT, nonseminomatous germ cell tumors,... 

Elevated human chorionic gonadotropin (hCG) levels are seen in pregnancy, trophoblastic diseases, and germ cell tumors. It is a useful tumor marker for tumors of the placenta (trophoblastic tumors) and some tumors of the testes. It is also useful for diagnosing and monitoring pregnancy (see Chapter 54 for a discussion of hCG and pregnancy). 

Serum AFP levels are elevated in hepatocellular carcinomas and malignancies involving ovaries and testes. Yolk sac tumors, which occur more frequently in the ovaries of young women, and girls, and in the testes of boys, raise serum levels of AFP. Serum hCG measurement is also helpful in the diagnosis and management of germ cell tumors. Thus, hCG and AFP are also used as tumor markers. 

Although the previously mentioned markers are helpful in distinguishing between different germ cell tumors, they are not entirely specific. CD 117 or c-kit is a marker of interstitial cell of Cajal (and therefore stains gastrointestinal stromal tumors), mast cells, and melanocytes in addition to germ cells.CD30 (+ in embryonal carcinoma) is an activation marker, often seen in... 

Giwercman A, Andrews PW, Jorgensen N, et al. Immunohistochemical expression of embryonal marker TRA-1-60 in carcinoma in situ and germ cell tumors of the testis. Cancer. 1993 72 1308-1314. 

Bosl GJ, Ilson DH, Rodriguez E, et al. Clinical relevance of the i(12p) marker chromosome in germ cell tumors. J Nall Cancer Inst. 1994 86 349-355. 

Hoei-Hansen CE, Nielsen JE, Almstrup K, et al. Transcription factor AP-2gamma is a developmentally regulated marker of testicular carcinoma in situ and germ cell tumors. Clin Cancer Res. 2004 10 8521. 

Pauls K, Jager R, Weber S, et al. Transcription factor AP-2gam-ma, a novel marker of gonocytes and seminomatous germ cell tumors. Int J Cancer. 2005 115 470. 

Malignant germ cell tumors comprise, in order of decreasing frequency, dysgerminomas, immature teratomas, endodermal sinus tumors, and embryonal and nongestational choriocarcinomas. The latter three are extremely rare. In these patients, tumor markers may be helpful for assessing response and tumor recmrence. Endodermal sinus tumors secrete AFP. Embryonal carcinomas can secrete both AFP and HCG, whereas pure choriocarcinomas secrete only HCG [4]. 

Determination of AFP levels in amnio tic fluid or maternal serum is used for antenatal screening for certain birth defects and chromosomal abnormafities in the fetus (see Chapter 54). Elevated maternal serum AFP indicates the possibility of a neural tube or open abdominal wall defect in the fetus. The levels may also be elevated with multiple fetuses, low birth weight, fetal demise, and incorrect estimation of gestational age. Trisomy 21 (Down syndrome) and trisomy 18 are associated with low maternal serum AFP levels. AFP is also used as a marker for hepatocellular and germ cell carcinomas. For a discussion of the role of AFP as a tumor marker, see Chapter 23. 

FIGURE 18.40 Dysgerminoma. Strong nuclear staining for Oct-4, as shown here, is characteristic of dysgerminoma. In the ovary, the only other tumor types that stain for this marker are embryonal carcinoma and the germ cells in gonadoblastoma. 

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