RISK FACTORS OF CANCER

What are some unavoidable risk factors for cancer?

Aging and heredity.

What percentage of cancers does WHO estimate to be preventable?

30–50%.

How does early detection help in cancer prevention?

Through early diagnosis, treatment, and screening to reduce cancer burden.

Why is age considered the most important cancer risk factor?

Most cancers occur in older adults; median age in the US is 66 years.

Which cancers are more frequent in children?

Neuroblastoma, childhood leukemia, and some bone cancers.

How does alcohol increase cancer risk?

Through DNA damage, inhibition of repair, inflammation, and hormonal effects.

Which cancers are associated with alcohol use?

Mouth, throat, larynx, esophagus, liver, breast, and colorectal cancer.

What is the role of acetaldehyde in alcohol-induced cancer?

It damages DNA and blocks its synthesis and repair.

What is CYP2E1's role in alcohol metabolism?

It generates reactive oxygen species that damage DNA.

Can red wine prevent cancer due to resveratrol content?

No, there is no evidence it prevents cancer.

What are environmental carcinogens?

Substances in air, water, food, industrial emissions, or household materials.

Name three well-known environmental carcinogens.

Aflatoxins, asbestos, and arsenic.

How does benzene cause cancer?

It is a known mutagen and carcinogen linked to blood cancers.

What cancers are associated with wood dust exposure?

Nasal and sinus cancers.

How does secondhand smoke act as a carcinogen?

It contains toxic compounds similar to active smoking, increasing cancer risk.

How does chronic inflammation contribute to cancer?

By causing DNA damage and promoting mutations.

Name two conditions that can lead to cancer via chronic inflammation.

Inflammatory bowel disease and untreated wounds.

What is the role of NFkB and STAT3 in cancer?

They promote tumor growth and suppress antitumor immunity.

Which inflammatory cytokines promote tumor progression?

IL-1, IL-6, TNF, and PGHS-2.

What are the pathways through which inflammation promotes cancer?

Intrinsic and extrinsic pathways activating transcription factors.

How does diet influence cancer risk?

Diets high in fat, processed meat, and refined carbs increase cancer risk.

What lifestyle change can reduce cancer risk by up to 70%?

A healthy diet and active lifestyle.

Which cancers are diet-related in women?

Breast and endometrial cancers.

Which cancers are diet-related in men?

Prostate and gastrointestinal cancers.

What type of food is thought to be protective against cancer?

Fresh fruits and vegetables.

How do hormones influence cancer development?

They promote cellular proliferation and hyperplasia.

What hormone therapy once caused cancer in daughters of treated women?

Diethylstilbestrol (DES).

What is a cancer risk associated with anabolic steroid use?

Prolonged use may lead to cancer via uncontrolled cell proliferation.

How do oral contraceptives affect cancer risk?

Oestrogen-only and combined pills may increase breast cancer risk.

How do hormones interact with gene expression in cancer?

By stimulating pathways that promote tumor cell growth.

Why are immunosuppressed individuals at higher cancer risk?

Due to reduced immune surveillance against abnormal cells.

What types of cancer are common after organ transplantation?

Non-Hodgkin lymphoma, liver, lung, and kidney cancers.

Which virus is linked to cervical and anal cancer in HIV/AIDS patients?

Human papillomavirus (HPV).

What virus causes Kaposi sarcoma in immunocompromised patients?

Human herpesvirus 8 (HHV-8).

How does HIV increase cancer risk?

Through immunosuppression and co-infection with oncogenic viruses.

How is EBV linked to cancer?

It is associated with some NHLs and nasopharyngeal carcinoma.

Which cancers are caused by Hepatitis B and C viruses?

Liver cancer.

How is Hepatitis B prevented and Hepatitis C treated?

HBV: vaccination; HCV: now curable with antivirals.

Which virus causes adult T-cell leukemia/lymphoma?

HTLV-1.

How is HHV-8 transmitted?

Saliva, blood, or organ transplantation.

What bacterium is associated with gastric lymphoma and carcinoma?

Helicobacter pylori (H. pylori).

How is H. pylori transmitted?

Contaminated food or mouth-to-mouth contact.

Which parasite causes bladder cancer in Africa?

Schistosoma haematobium.

How is Schistosoma transmitted?

Through cercaria from freshwater snails penetrating the skin.

What is the role of MALT in H. pylori-related cancers?

It leads to MALT lymphoma in the stomach lining.

How does obesity contribute to cancer?

It increases risk of several cancers due to hormonal and metabolic changes.

Which cancers are more common in obese individuals?

Colon, rectum, endometrium, esophagus, kidney, pancreas, and gallbladder.

Which group is at higher risk for breast cancer due to obesity?

Postmenopausal women.

What is the mechanism linking fat to cancer?

Adipose tissue alters estrogen and insulin levels, promoting cancer.

How does obesity affect inflammation?

It causes chronic low-grade inflammation, which can promote cancer.

What type of radiation causes DNA damage?

Ionizing radiation (e.g. X-rays, gamma rays, radon).

What is the risk from non-ionizing radiation?

No significant DNA damage; generally considered safe.

How does radon exposure lead to cancer?

It accumulates in lungs and causes lung cancer.

Why are medical workers monitored for radiation exposure?

To reduce cancer risk from diagnostic imaging.

How does radiation therapy sometimes cause secondary cancers?

Through exposure to nearby healthy tissues.

How does sunlight exposure cause skin cancer?

UVB radiation damages DNA.

Why are albinos more susceptible to sun-induced skin cancer?

They lack melanin for protection.

What types of skin cancer are caused by UV radiation?

Squamous cell and basal cell carcinoma.

When is UV exposure most dangerous?

Mid-morning to late afternoon.

Can people with dark skin get skin cancer from sunlight?

Yes, all skin tones are susceptible.

What is the most preventable cause of cancer?

Tobacco use.

Which cancers are strongly linked to smoking?

Lung, mouth, throat, bladder, kidney, liver, pancreas, and more.

What cancers can result from smokeless tobacco use?

Mouth, esophagus, and pancreatic cancer.

How does tobacco cause cancer at a molecular level?

Through carcinogens that mutate DNA.

How does secondhand smoke affect non-smokers?

It exposes them to the same carcinogens and increases cancer risk.

development in HIV/AIDS?

Reactivation of HHV-8 in the context of immunosuppression.

Why are anal and cervical cancers common in HIV patients?

Due to co-infection with high-risk human papillomavirus (HPV).

How does HAART treatment relate to cancer risk in HIV?

Cancer can still develop despite HAART, though incidence may decline.

What is the global prevalence of H. pylori?

About two-thirds of the world’s population harbors the bacterium.