CANCER FAMILIES, which have long been a source of information on rare inherited malignancies, are beginning to provide insights into the development of common cancers as well.
What investigators are finding is that, at the level of the gene, rare and common forms of cancer have a great deal in common. Many apparently result from the same aberrations in the genome.
The difference is basically one of timing. Persons with inherited forms of cancer are born with at least one aberration transmitted from the parent; those with sporadic forms of the disease develop these aberrations later in life.
Through studying the familial forms of the disease, investigators have attained a better idea of how a cell becomes malignant. Most now agree with the multi-hit hypothesis propounded in 1971 (to explain familial carcinogenesis) by Alfred Knudsen, PhD, Fox Chase Cancer Center, Philadelphia. Knudsen proposed that carcinogenesis requires more than one genetic