Many of the medical and scientific terms used in this summary are found in the NCI Dictionary of Genetics Terms. When a linked term is clicked, the definition will appear in a separate window.
Many of the genes described in this summary are found in the Online Mendelian Inheritance in Man (OMIM) database. When OMIM appears after a gene name or the name of a condition, click on OMIM for a link to more information.
There are several hereditary syndromes that involve endocrine or neuroendocrine glands,...
It is estimated that 8,820 new cases of testicular cancer will be diagnosed in men, and 380 men will die of this disease in the United States in 2014.Testicular cancer is the most common malignancy in men aged 15 to 34 years.[2,3] It accounts for approximately 1% of all cancers in men. Worldwide, testicular cancer has more than doubled in the last 40 years. Incidence varies considerably in different geographical areas, being highest in Scandinavia and Switzerland; intermediate in the United States, Australia, and the United Kingdom; and lowest in Asia and Africa. It also varies according to ethnic groups, with a much higher rate among whites than blacks in the American population. An annual increase of 3% is reported for Caucasian populations. Despite the increase in observed incidence, there has been a dramatic decrease in mortality as a result of effective treatments.
Unlike most other cancers, testicular cancer is generally found in young men. In white men, testicular cancer is the most common cancer from age 20 years to age 34 years, the second most common from age 35 years to age 39 years, and the third most common from age 15 years to age 19 years.
Approximately 69% of testicular cancers are localized, 18% are regional, and 12% are distant stage at diagnosis. Although there has been no appreciable change in the stage distribution at diagnosis, advances in treatment have been associated with a 60% decrease in mortality. The majority of testicular cancers are curable even at advanced stages, and it would be impractical to document a further decrease in mortality associated with screening.
Germ cell tumors (GCTs) of the testis constitute 94% of testicular tumors and include five basic cell types:
Sixty percent of GCTs are seminomas; the remainder are nonseminomatous GCTs. Almost half of all GCTs contain more than one of the five cell types.
Three subtypes of pure seminomas have been described: classic, anaplastic, and spermatocytic. Classic seminoma accounts for 80% to 85% of all seminomas and occurs most commonly in men aged 30 to 50 years. Anaplastic seminoma accounts for 5% to 10% of all seminomas and has an age distribution similar to that of the typical subtype. A number of features suggest that anaplastic seminoma is a more aggressive and potentially more lethal variant of typical seminoma. These characteristics include greater mitotic activity, higher rate of local invasion, increased rate of metastatic spread, and higher rate of tumor marker (human chorionic gonadotropin [hCG] beta, or beta hCG) production. Spermatocytic seminoma accounts for 2% to 12% of all seminomas, and nearly half occur in men older than 50 years. The cells closely resemble different phases of maturing spermatogonia. The metastatic potential of this tumor is extremely low, and the prognosis is favorable.