Essential Cell Biology 5th edition

A:56 Answers
cells, thereby increasing cell numbers in hormone-sensitive
organs such as breast, uterus, and prostate. The increase
in cell division boosts the mutation rate per cell, because
mutations, regardless of environmental factors, are
spontaneously generated in the course of DNA replication
and chromosome segregation. The increase in cell numbers
increases the total pool of cells at risk. In these and possibly
other ways, the hormones can favor the development of
cancer, even though they do not directly cause mutations.
ANSWER 20–19 The short answer is no—cancer in general
is not a hereditary disease. It arises from new mutations
occurring in our own somatic cells, rather than from
mutations we inherit from our parents. In some rare types
of cancer, however, there is a strong heritable risk factor,
so that parents and their children both show the same
predisposition to a specific form of the disease. This occurs,
for example, in families carrying a mutation that knocks
out one of the two copies of the tumor suppressor gene
APC; the children then inherit a propensity to colorectal
cancer. Much weaker heritable tendencies are also seen in
several other cancers, including breast cancer, but the genes
responsible for these effects are still mostly unknown.