Does Cancer Actually Run in Families?
Jan 14, 2022
Source: Cainiu Health
Dr. Shi Jizhou
Introduction
Does Cancer Run in Families?
It is generally believed that hereditary cancers account for only 1%–3% of all cancers worldwide, and only a small number of malignant tumors have a familial or inherited background. In families with hereditary cancer, parents may pass on cancer-causing mutated genes to their children. However, carrying such a mutated gene merely indicates an increased risk and likelihood of developing cancer.
Cancer exhibits a certain degree of hereditary predisposition. Examples include breast cancer, retinoblastoma, colorectal cancer, and ovarian cancer—these cancers carry relatively high genetic risks and can be transmitted to offspring via inherited gene mutations. Therefore, individuals diagnosed with cancer should prioritize appropriate cancer treatment. Moreover, for cancers with known hereditary tendencies, it is generally advisable to avoid pregnancy to reduce the risk of passing on cancer susceptibility to the next generation. Consequently, preconception health examinations for both partners are strongly recommended.
Is Cancer Hereditary?
It is widely accepted that hereditary cancers account for only 1%–3% of all human cancers, and only a small proportion of malignant tumors have a familial genetic background. In such hereditary cancer families, parents may pass tumor-predisposing mutated genes to their children. However, it must be emphasized that inheriting a disease-associated mutation does not mean the individual already has cancer; rather, it signifies an increased risk and likelihood of developing cancer later in life. Thus, having a family history of cancer does not guarantee that an individual will develop the disease.
Which Cancers Exhibit Hereditary Predisposition?
(1) Colorectal Cancer
Familial adenomatous polyposis (FAP) is a condition highly prone to progression into colorectal cancer. Observations indicate that if a parent develops colorectal cancer due to FAP, their children face up to a 50% risk of developing the same type of cancer.
(2) Breast Cancer
Women whose mother or sister has had breast cancer face a threefold higher risk of developing breast cancer themselves compared to the general female population. Thus, besides age, diet, obesity, and other factors, genetics plays a significant role in breast cancer development. Additionally, bilateral breast cancer demonstrates particularly strong hereditary features.
(3) Retinoblastoma
Some cases of retinoblastoma are associated with genetic defects. This is a malignant tumor predominantly affecting children. Approximately one-third of patients present with bilateral disease, which follows an autosomal dominant inheritance pattern—meaning multiple generations within a family (e.g., grandparents, parents, and children) may be affected. The remaining two-thirds present with unilateral disease, among which roughly 10% are still attributable to hereditary causes.
(4) Lung Cancer
Reports indicate that individuals with a first-degree relative diagnosed with lung cancer—and who also smoke—face a 14-fold increased risk of developing lung cancer compared to the general population. Japanese studies have shown that 35.8% of patients with squamous cell lung carcinoma have a family history of the disease; among women with alveolar cell carcinoma, this figure rises to 58.3%.
The above provides an overview of whether cancer is hereditary. We hope this information is helpful to you.
