Introduction to cancer entities

Question 1

Name the four main types of cancer.

Answer 1

1. Carcinoma:
   - Arise in epithelial tissue
2. Sarcoma:
   - Arise from connective tissue
   - In bones, tendons, cartilage, muscle and fat
3. Leukemia:
   - Cancers of the blood
   - Originates in bone marrow
4. Lymphoma:
   - Cancers of the lymphatic system

Question 2

Which are the three types of Carcinoma ?

Answer 2

1. Adenocarcinoma
   - Develop in glandular epithelial cells of lungs, colon, breast and pancreas
2. Squamous cell carcinoma
   - Develop in squamous epithelium of skin, esophagus, lungs and cervix
3. Transitional cell carcinoma
   - Develop in the transional epithelium of bladder, renal pelvis and ureters

Question 3

Name the five most common cancers in descending order.

Answer 3

• Breast cancer
• Lung cancer
• Colorectal cancer
• Prostate cancer
• Stomach cancer

Question 4

Name six risk factors for lung cancer.

Answer 4

• Smoking
• Radon
• Asbestos
• Arsenic
• Radioactive ores
• Inhaled chemicals

Question 5

Name six risk factors for colon cancer.

Answer 5

• Age > 50 years
• Diet: High in red meats and low in vegetables
• Obesity
• Smoking
• Alcohol consume
• Genetics

Question 6

Name five general risk factors for cancer development.

Answer 6

• Genetic mutations
• Lifestyle
• Environmental factors
• Pathogens
• Other diseases

Question 7

Mutations in which kind of genes often cause cancer ?

Answer 7

• Oncogenes
• Tumor suppressor genes
• DNA repair genes

Question 8

What is Metastasis ?

Answer 8

• The process by which cancer cells spread from the primary site to distant organs
• Thereby, cancer cells travel via blood or lymphatic routes

Question 9

Name two types of cancer which are not common but is often lethal.

Answer 9

• Pancreatic cancer
• Brain tumors

Question 10

Name three reasons why rare cancers nevertheless have a high mortality rate.

Answer 10

• Lack of reliable screening tools or biomarkers leading to a delayed diagnosis
• Tumor location limits treatment options (e.g. in the brain)
• Resistance to conventional and advanced therapies

Question 11

Name two exogenous cancer risk factors.

Answer 11

• Carcinogens (e.g. UV light, radiation)
• Viruses (e.g. HPV, EBV)

Question 12

Name three encogenous cancer risk factors.

Answer 12

• Inflammation
• Oxidative stress
• Hormonal imbalances

Question 13

What are the three key stages of tumorigenesis ?

Answer 13

1. Initiation:
   - DNA damage by carcinogens or replication errors
2. Promotion
   - Clonal expansion of mutated cells
   - Often promoted by chronic inflammations or hormones
3. Progression
   - Acquisition of additional mutations
   - Enable angiogenesis to increase the blood supply
   - Tissue invasion
   - Immune escape

Question 14

After how many divisions do somatic cells enter senescence ?

Answer 14

• After 60-80 divisions
• Time points depends on the length of the telomeres

Question 15

How can cancer cells bypass senescence ?

Answer 15

• By inactivating the p53/RB pathway
• By activating the telomerase reverse transciptase (TERT)