Cancer growth and progression are not a single reason-centric, but multiple factors jointly responsible for the occurrence of this deadly disease. The causative factors of cancer may involve genetic reasons, environmental interference, or the lifestyle pattern of an individual.
The reason for childhood cancer and adult cancer differs. Usually, the stem cells of a child are attacked at the beginning of childhood cancer. Stem cells are specialized cells that can produce specialized essential cells for the body. A sporadic mutation or unexplained cellular changes is responsible for childhood cancer.
Epithelial cells become more commonly cancerous in the case of adult cancer. Epithelial cells are covering the body surface and also present at the lining of the body cavity. Prolonged exposure to environmental carcinogens is responsible for epithelial cancer growth. Therefore, often adult cancers are acquired for a variety of reasons.
Genetic involvement in cancer development
Genetics: inheritance and family history play important role in certain childhood cancers. The family history of cancer may influence genetic mutation or exposure to carcinogenic because of industrial area near the family’s residence or joint approach or just a coincidence can cause familial cancer.
Genetic disorders: some genetic disorders like Wiskott-Aldrich and Beckwith-Wiedemann syndrome alter the immune system functioning. The immune system of our body plays a primary role in defense mechanisms and protects from infections and other diseases. The mature bone marrow plays an important role in immune system functioning. One theoretical explanation reported that defects in the bone marrow present in the cells, or stem cells induce abnormality in cells that lead to cancer cells. The cause of stem cell defect may occur due to inherited genetic disorder or exposure to toxins and certain viruses.
Recently medical science discovers certain types of faulty genetic alterations present in more than 90% of cancer cases. Researchers explain mutation of oncogenes, Tumor suppressor genes and Mismatch-repair genes may due to inherent reason or acquired from an environmental exposure can cause cancer development.
Oncogenes: The normal cell growth is regulated by oncogenes. The oncogenes are suddenly flipping their characteristics and unable to control normal cell growth. This leads to cancer progression.
Tumor suppressor genes: These genes can identify abnormal growth, damaged cells, or cancer cells’ growth and also obstruct their reproduction until the defect is corrected. Impairment of Tumor suppressor genes may due to faulty mutation or other reason can cause cancerous tumor growth.
Mismatch-repair genes: These genes help in the identification of erroneous DNA coping to produce a new cell. These genes repair the mismatched DNA and correct them. Impaired functioning of these genes leads to the transmission of erroneous DNA to new cells, causing cell damage.
Other possible risk factors in cancer development
Cancer in adults has been associated with repetitive exposure to risk factors. Risk factors increase the chance to develop unwanted changes in the body, which make the body less resistant to withstand cellular disorders. The following risk factors and faulty mechanisms have a direct and indirect contribution to cancer development:
Lifestyle factors: occupational hazardous like a high-fat diet, smoking, working with toxic chemicals are some examples of poor lifestyle measures. These may increase the risk of adult cancers.
Environmental exposures: Pesticides, fertilizers, and other carcinogen exposure have a direct link to developing childhood cancers.
High-dose chemotherapy and radiation: In some cases, cancer patients, especially children who have been exposed to a high dose of radiation or chemotherapeutic agents may cancer reoccur as a second malignancy later in life. The immune system alterations due to strong anticancer agents can cause the recurrence of cancer.
Certain viral infections: Epstein-Barr virus and HIV have linked to an increased risk of a certain type of childhood cancer developments including Hodgkin and non-Hodgkin lymphoma. It is assumed that these viruses alter cellular functioning. Cellular alteration leads to cancer development and reproduces more number of cancer cell developments.