Haematological Malignancies - Genetics

Question 1

Haematological Malignancies

GENETICS

Answer 1

t (9;22) = PHILADELPHIA CHROMOSOME

• present in > 95% patients with CML
• part of Abelson porto-oncogene moved to BCR gene on chromosome 22 > results in BCR-ABL gene which codes for a fusion protein which has excessive tyrosine kinase activity
• Philadelphia chromosome = good prognosis in CML, bad prognosis in ALL

t(15;17) = Seen in Acute Promyelocytic Leukaemia (M3)
- fusion of PML and RAR-alpha genes

t(8;14) = Burkitt’s Lymphoma
- MYC oncogene is translocated to immunoglobin gene

t(11;14) = Mantle cell lymphoma
- Deregulation of cyclin D1 (BCL-1) gene

Question 2

Haematological Malignancies

Genetics and Prognosis

Answer 2

CML - Philadelphia Chromosome 9:22 - good prognosis

CLL

• Deletion of long arm of chrom 13 = good prognosis
• Deletion of short arm of chrom 17 = poor prognosis

AML

• Deletion of chromosomes 5 or 7 = poor prognosis
• APML assoc with t(15:17) = good prognosis (subtype 3)

ALL

• Philadelphia translocation 9:22 = poor prognosis
• FABL3 type = poor prognosis
• Deletion of 9p = good prognosis
• FABL1 = good prognosis