The Hereditary Factor in Human Neoplasms

Abstract

Clinical experience shows that when more than one member of a family has a neoplasm, the other members are apt to show the same type of tumor in the same organ and at about the same age. When these three factors are considered, and when the incidence of the neoplasm in question in the general population is taken into account, it becomes obvious that chance alone fails to explain the occurrence of the same type of neoplasm in the same organ in more than one member of the family. Heredity is the only possible explanation. The occurrence of the same tumor in identical twins further strengthens the statement that neoplasms are inherited. Lengthy pedigrees are not necessary to establish the fact of inheritance; although they are useful in determining the manner of transmission.