Neoplasia II

Question 1

carcinogenesis

Answer 1

process by which normal cells are transformed into cancer cells through the accumulation of nonlethal genetic damage (mutations)

• mutations may be acquired by the action of chemicals, radiation, viruses, or they may be inherited
• a tumor results from clonal expansion of a single mutated cell

Question 2

What are the four classes of regulatory genes?

Answer 2

• growth-promoting proto-oncogenes
• growth-inhibiting tumor suppressor genes (anti-oncogenes)
• genes that regulate programmed cell death (apoptosis)
• genes involved in DNA repair

Question 3

Carcinogenesis is a multistep process

What are the seven fundamental changes that occur during the development of a neoplasm?

Answer 3

• self-sufficiency in growth signals
• insensitivity to growth-inhibitory signals
• evasion of apoptosis
• limitless replication
• sustained angiogenesis (neoplasms induce new vessel growth)
• ability to invade and metastasize
• defects in DNA repair

Question 4

What are the four steps in chemical carcinogenesis?

Answer 4

• initiation
• promotion
• progression
• cancer

Question 5

Major chemical carcinogens are classified into what two groups?

Answer 5

• indirect acting

- direct acting

Question 6

What are a few examples of carcinogenic hcemicals?

Answer 6

• alkylating agents
• tobacco
• naturally occurring carcinogens (ex: Aflatoxin B1 which causes a mutation in the p53 gene, a tumor suppressor gene, and is associated with hepatocellular carcinoma)

Question 7

What are examples of some oncogenic viruses?

Answer 7

• human papillomavirus (HPV)
• Epstein Barr virus (EBV)
• Hepatitis B and C viruses (HBV, HCV)

Question 8

What are four possible effects of a tumor on the host?

Answer 8

• local effects
• hormonal effects
• cachexia
• paraneoplastic syndromes

Question 9

Grading of a cancer is based on the following histologic features:

Answer 9

• Grade 1 (well-differentiated): resembles normal counterpart, in architecture and cytology
• Grade 2 (moderately-differentiated): intermediate
• Grade 3 (poorly-differentiated): minimal resemblance to normal, disorganized, high nuclear:cytoplasmic ratio, many mitoses, necrosis often present

Question 10

The TNM system for cancer staging is based on what three features of neoplasm?

Answer 10

• size (or depth of invasion) of the primary tumor (T - extent of Tumor)
• extent of spread beyond the primary tumor to regional lymph nodes (N - lymph Node involvement)
• metastases (M - presence of Metastases)

*stage of cancer is very important in determining the prognosis of the patient