Neoplasia II

Question 1

what percentage of (malignant) tumor cells are typically in S phase?

Answer 1

20-80%

Question 2

what are the factors that determine increased growth rate?

Answer 2

1. doubling time 2. fractions of tumor cells in proliferative pool 3. cell production vs cell loss

Question 3

what are indicators of proliferation?

Answer 3

1. mitotic activity 2. Ki-67 protein elevated 3. high PCNA score

Question 4

Ki-67 and PCNA are indicators for what tumorogenesis parameter?

Answer 4

proliferation

Question 5

when is cell atypia observed?

Answer 5

pre-malignant and malignant tumors

Question 6

how is cell atypia recognized?

Answer 6

cellular pleomorphism and nuclear changes (N:C ratio, hyperchromasia)

Question 7

what are tumor giant cells?

Answer 7

represent anaplasia; single huge polymorphic nucleus or >2 nuclei that are large and/or hyperchromatic

Question 8

definition: desmoplasia

Answer 8

hyperplasia of activated fibroblasts

Question 9

where is desmoplasia most commonly observed?

Answer 9

breast and liver cancer

Question 10

what are the important factors involved in tumor angiogenesis?

Answer 10

VEGF and FGF

Question 11

what are the pro-angiogenic factors of a tumor?

Answer 11

VEGF, bFGF, HIF

Question 12

what are the anti-angiogenic factors of a tumor?

Answer 12

1. thrombospondin-1 2. angiostatin 3. endostatin 4. tumstatin

Question 13

why do malignant tumors show central necrosis?

Answer 13

outgrow blood supply, results in ischemic necrosis