Every cancer is caused by damage in genes, which is so called mutation in biological terms. In some cases, cancer is caused by hereditary causes and these cancers are called hereditary cancer. Some people born with gene mutations which in later stages of their life develops into cancer. More than 10% of cancer is caused by hereditary reasons.
Hereditary cancer occurs in a much earlier stage comparing to normal one. So prediction test is highly recommended for people with positive cancer history. In these cancers, the mutated gene transfer from parent to children. Sometime there also chances of getting mutated genes from close relatives.
People inherited with mutated genes have a chance of developing different kinds of cancer, which in turn makes the life of cancer survivors difficult and this affects the course of treatment as it requires some special treatments.