According to the American Cancer Society: A breast cancer is a malignant tumor that starts from cells of the breast. A is a group of cancer cells that may grow into (invade) surrounding tissues or spread (metastasize) to distant areas of the body. Breast cancer occurs mainly in women, but men can get it, too. Many people do not realize that men have breast tissue and that they can develop breast cancer.
So whether you call them moobs or 'man'ary glands, the man boobs are also susceptible to breast cancer development. Though there is no for sure cause for men developing breast cancer, there are risk factors described by the ACS which include the following:
Age: Men with breast cancer are on average about 68 years old when they are diagnosed.
Family history: About 1 out of 5 men with breast cancer have close male or female relatives with the disease.
Genetics: The BRCA2 mutations may account for 1 in 10 men.
Alcohol/Liver disease: excessive alcohol abuse may cause liver disease which may in turn mess with the hormone balance
Estrogen treatment: Estrogen based treatments are sometimes used in prostate cancers, as well as those who may have had a sex change.
Obesity: fat cells can change male hormones into female hormones
Testicular Conditions: more research is needed
Klinefelter's Syndrome : though more research is needed, the extra X chromosomes related with the genetic disorder may account for some cases.
Certain Occupations : more research is needed but prolonged exposure to heat and fumes may have an affect on cancer development
All information found on American Cancer Society website. As with anything: I am not a doctor. I don't pretend to be. I just found it share worthy. Talk with the moob owner in your life, and get him checked too, especially if it runs in the family.