“Ask Dr. HKSH” - Is Cancer Hereditary?

Dr. LIANG Hin Suen, Raymond

Specialist in Haematology & Haematological Oncology

Q1. What is the relationship between genes and cancer?

All cancer cells originate from normal cells that undergo oncogenic mutations. When normal cells have these genetic changes, they may transform into cancer cells. Typically, this involves multiple genetic changes, not just a single one.

Q2. Are genetic changes inherited?

While our genes are inherited from our parents, genetic changes may also occur later in life. As our genes are replicated whenever the cells multiplied, errors may occur during the process. Normal cells may then become cancerous, if such errors occur in critical oncogenic genes.

Q3. Is cancer caused by genetic factors?

Some genes are linked to cancer. If you inherit these genes from your parents, you may have a higher risk of developing cancer. If your family has a strong history of cancer and many relatives have had cancer, you should be vigilant. You may have inherited genetic mutations that predispose cancer. When this combined with further acquired genetic changes, normal cells may become cancerous, leading to malignant tumour formation.

Q4. What are the common hereditary cancers?

Two cancers may sometimes have a hereditary component: colorectal cancer and breast cancer. Some colorectal or breast cancer patients may carry genetic mutations inherited from parents, making them more susceptible to these cancers.

Q5. Is blood cancer also hereditary?

Like other cancers, blood cancer is also caused by genetic changes. In most cases, it results from acquired mutations rather than inherited ones. It is rarely linked to inherited genetic mutations. For example, some infants are diagnosed with blood cancer shortly after birth. They are more likely to have inherited cancer-causing genes, which leads to an early onset of blood cancer. In adults, while blood cancer could also be associated with inherited mutations, such occurrence is very rare. I have recently treated a patient with acute myeloid leukaemia. He has an inherited genetic mutation that makes him more likely to develop leukaemia. While such cases are extremely rare, we must be cautious. This patient needs a bone marrow transplant from siblings or relatives; They may not be suitable donors if they also carry the same cancer-causing gene.

Q6. What should I do if multiple family members have had cancer?

If many of your family members have had cancer, especially of the same type, you should be proactive about checking for inherited cancer-causing genes. If you have concerns, consult a doctor and consider genetic testing to determine if you carry these hereditary cancer genes.

Q7. What should I do if I find out I carry a cancer gene?

If you’ve indeed inherited a cancer-causing gene, you should take extra precautions. For cancers like colorectal or breast cancer, start cancer screening early in life. Early detection through screening can lead to timely treatment.

Q8. Should I consider having children if I or my partner carry a cancer gene?

If you’re concerned about passing a cancer-causing gene to your children and the gene is known, you may undergo genetic testing. You may opt for assisted reproduction and select unaffected embryos to avoid passing the cancer gene to the next generation.