Which among the following pairs of Oncogenes is activated by Translocation?-
**Core Concept**
Activation of oncogenes by translocation is a common mechanism of tumorigenesis, particularly in hematological malignancies. This involves the fusion of parts of two different chromosomes, resulting in the creation of a new fusion gene that encodes a constitutively active protein.
**Why the Correct Answer is Right**
The correct pair of oncogenes activated by translocation is BCR-ABL. This occurs due to the t(9;22) chromosomal translocation, also known as the Philadelphia chromosome. As a result, the BCR gene on chromosome 22 fuses with the ABL1 gene on chromosome 9, creating a chimeric protein with constitutive tyrosine kinase activity. This leads to uncontrolled cell proliferation and is commonly seen in Chronic Myeloid Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL).
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the MYC oncogene is typically activated by amplification or overexpression, not by translocation.
**Option C:** This option is incorrect because the JAK2 oncogene is typically activated by mutation (e.g., V617F), not by translocation.
**Clinical Pearl / High-Yield Fact**
The Philadelphia chromosome is a classic example of a chromosomal abnormality that can be detected by cytogenetic analysis or FISH (Fluorescence In Situ Hybridization). It is a key diagnostic feature of CML and some cases of ALL.
**Correct Answer:** B. BCR-ABL.