Precursor B and T neoplasms

Question 1

neoplastic popln of immature lymphocytes

Answer 1

lymphoblasts

Question 2

Pre-B vs Pre-T ALL

Answer 2

B: leukemic (blood and BM)
T: lymphotic - mediastinal mass

Question 3

When is incidence of Pre-B and Pre-T ALL highest?

Answer 3

B- 4 yo

T- adolescence

Question 4

What is the most common cause of cancer in children?

Answer 4

ALL

Question 5

Important clinical features of ALL

Answer 5

• Abrupt “stormy” onset
• Bone pain
• CNS sx

Question 6

Morphology of ALL

Answer 6

B and T look same

• effacement of normal architecture (BM)
• blasts: small cells w/ high N:C ratio, irregular nuclear contour, smooth chromatin pattern
• MPO negative

Question 7

Immunophenotype - what is found on both pre-B and pre-T neoplasms?

Answer 7

CD34

TdT

Question 8

Pre-B lymphoblast immunophenotype

Answer 8

CD19, CD22, CD10, CD79a

surface light chain negative

Question 9

Pre-T lymphoblast immunophenotype

Answer 9

CD1a, CD2, CD5, CD7

cCD3, CD4, CD8

Question 10

What type of mutation is seen with Pre-B? Pre-T?

Answer 10

B- loss of function

T- gain of function

Question 11

Translocations in Pre-B:

t(12,21)

t(9;22)

Answer 11

• ETV6, RUNX1 genes

- BCR-ABL genes

Question 12

What is the mutation seen with Pre-T

Answer 12

NOTCH1

Question 13

General theme of cytogenetics in Precursor neoplasm

Answer 13

translocations – dysregulate expression and function of TF needed for normal cell maturation

Question 14

Pre- B - good prognosis

Answer 14

hyperdiploidy
t(12;21)
t(9;22)

Question 15

Complete remission rate with ALL is seen in ______

Answer 15

Children

Question 16

Translocation in Pre-T

Answer 16

t(7;14)

Question 17

What is a favorable prognostic factor for ALL

Answer 17

age 2-10
early Pre-B phenotype CD19/CD10
low WBC count
favorable cytogenetics: hyperploidy, t(12;21), trisomies 4,7,10