Ph+ ALL

Synonyms

Philadelphia chromosome-positive ALL, Ph+ Acute Lymphoblastic Leukemia,

Overview

About 25 percent of adults with ALL have a subtype called “Ph-positive ALL” (also known as “Ph+ ALL” or “Philadelphia chromosome-positive ALL”). The leukemia cells of these patients have the Philadelphia chromosome, which is formed by a translocation between parts of chromosomes 9 and 22. A piece of chromosome 9 breaks off and attaches to chromosome 22, and a piece of chromosome 22 similarly breaks off and attaches to chromosome 9. The abnormal chromosome 22 is known as the Philadelphia chromosome. This chromosomal alteration creates a fusion gene called BCR-ABL1. This gene produces a protein called a tyrosine kinase that causes the leukemia cells to grow and divide out of control.