Research globally points to four types of cancer-causing factors:

• Environmental factors: this includes contamination of the air, water, and food; overexposure to the sun; and long-term contact with chemicals such as asbestos.

• Lifestyle factors: including smoking, heavy drinking, poor diet, and stress.

• Hereditary factors: inheriting gene faults from your parents. For example, people who have family members with breast or colorectal cancer may have a higher risk of developing that cancer too.

• Viruses: some viruses can induce cancer. For example, the sexually-transmitted disease, Human Papilloma Virus (HPV), is cited as causing almost all cases of cervical cancer in women.