Pinciples of Neoplasia I

Question 1

What are the key features of neoplasia?

Answer 1

unregulated, irreversible, and monoclonal

Question 2

How do you determine the clonality of B lymphocytes?

Answer 2

Ig light chain phenotype: Ig is made of heavy and light chains. Each B cell expresses light chains that are either kappa or lamday, and normal kappa:lambda ratio is 3:1. Polyclonal hyperplasia maintains this ratio, while monoclonal neoplasia has ratios >6:1 or inverted ratios.

Question 3

What is an example of an epithelial neoplasm?

Answer 3

adenoma, papilloma are benign. (adenoma creates glands, papilloma creates papillary structures
If malignant, they are called “carcinomas”

Question 4

What is an expample of a mesenchymal neoplasm?

Answer 4

lipoma

if malignant, they are “sarcomas”

Question 5

How was clonality classically determined in non-B lymphocytes?

Answer 5

via G6PD isoforms. this is an x linked enzyme. In any given tissue in a woman, 50% would be one isoform and 50% would be another isoform, representing random X inactivation (assuming she inherited 2 different isoforms). Hyperplastic tissue would maintain this ratio, while neoplastic tissue would only express one isoform.
androgen receptor isoforms can also be used.

Question 6

How many divisions typically occur before the earliest clinical symptoms of cancer? What happens with each division?

Answer 6

About 30. but, every time cancer divides, there are increased mutations.