The cancer prevalence rate is increasing day by day. Nowadays, it is a common finding that more than one member of a family has got affected by cancer. But the connection of hereditary doesn’t need to be responsible for such events. Such incidence of cancer is considered sporadic due to acquired faulty gene mutation and that cannot pass on from generation to generation. Certain identified reasons of acquired faulty gene mutation ensue due to toxic environmental exposure or hormonal imbalance which can sporadically happen during cell division. The uncontrolled cellular growth leads to cancer development because harmful alterations (mutations) in the genetic messages (genes) cause unwanted cell growth.
But almost 5 to 10% of cancer incidences have familial connections and transmit hereditary. In general, all of us receive a maternal copy of the gene and another paternal copy of the gene to complete our genetic structure. But the passage of time leads to multiple mutations over a period that can interfere with cellular growth and trigger uncontrolled cell growth by repeated cell division. Eventually, repeated this action cause cancer.
In the case of hereditary cancers, individuals have a mutated growth control gene from one parent and a working copy of the identical gene received from their parent. The mutated gene is termed a “cancer susceptibility gene.” Every cell contains the cancer susceptibility gene with a working copy of the gene that helps to maintain the proper cell functioning in individuals who have hereditary cancer risk.
The chances of onset of hereditary cancer increase when the cell containing the working gene is damaged due to faulty mutation and lost growth control. Persons who have hereditary cancer history and inherited a cancer susceptibility gene usually experience cancer incidence in their lifespan. But the exception is also there.
However, in certain cases, individuals can also inherit damaged cancer susceptibility genes and pass them on to the next generation. Both genders have an equal risk of inheriting cancer susceptibility genes. There are 50% chances to pass on the cancer susceptibility gene a parent carries to their every child and cancer susceptibility also increases similarly. Like, every child has a 50% chance to inherit the working copy of the gene. Therefore, in chance cases, they have a similar risk of cancer development as other general populations.
It is necessary to mention that hereditary cancers link has gender-specific and may not pass on to both genders; for example, ovarian and prostate cancers. In certain cases, either of the parent act as a carrier of hereditary cancer for their next generation, though they are not affected.
There is no significant difference between hereditary and non-hereditary cancers. The cancer occurrence pattern in a family indicates the scope of hereditary cancer. Following are some sign which may help to indicate hereditary cancers:
- The same side of a family has a history of developing the same type of cancer in more than one relative.
- Repeated occurrence of cancer in a generation to generation
- Diagnosis of cancer at an early age
- Cancer affected patient has more than one type of primary cancer
- In a family, the incidence of genetically related cancers. (for example, ovarian and breast cancers, or uterine and colon cancers).
- Presence of hereditary cancer-associated signs like polyps and colon cancer, moles, and melanoma.
- Incidence of rare types of cancer
References:
https://health.uconn.edu/medical-genetics/hereditary-cancer-program/what-is-hereditary-cancer/
https://www.cancer.org/cancer/cancer-causes/genetics/family-cancer-syndromes.html