Comparison of Cytogenetic and Molecular Techniques Used for Philadelphia Chromosome Analysis: A Review Article

Abstract

Philadelphia chromosome is the characteristic hallmark of chronic myeloid leukemia and
refers to the translocation between chromosome number 9 (ABL) and 22 (BCR) resulting in a
shortened chromosome. The resulting ABL-BCR fusion gene encodes for tyrosine kinase
activity leading to uncontrolled growth of cell. The coining of Philadelphia chromosome by
Hungerford and Nowell went a long way in associating the genetic abnormality with cancer
formation in humans. This discovery played a pivotal role in cancer research and proved to be
a decisive episode in the arena of cancer cytogenetic. Their research was reported in Science
journal in 1960 and was a first major identification of a chromosomal deviation in the
neoplasm. A series of careful and repeated metaphase chromosomal observations led to the
conclusion that one of the acrocentric chromosomes was seen to be significantly reduced in
size and half of the long arm of this chromosome was missing. Different cytogenetic,
molecular and hematological techniques are used to diagnose CML. Most lately, PCR based
techniques have gained huge acceptance because of being sensitive and time efficient.
Keywords: Chronic myeloid leukemia, neoplasm, Philadelphia chromosome, Cytogenetic.