Philadelphia chromosome

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Philadelphia chromosome
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Fatigue, weight loss, night sweats, splenomegaly
Complications	Chronic myeloid leukemia, acute lymphoblastic leukemia, acute myeloid leukemia
Onset	Typically in adulthood
Duration	Long-term
Types	N/A
Causes	Genetic translocation between chromosome 9 and chromosome 22
Risks	Radiation exposure, benzene exposure
Diagnosis	Cytogenetic analysis, fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR)
Differential diagnosis	Other causes of leukemia
Prevention	N/A
Treatment	Tyrosine kinase inhibitors, chemotherapy, stem cell transplant
Medication	N/A
Prognosis	Improved with treatment
Frequency	Approximately 1-2 cases per 100,000 people per year
Deaths	N/A

Schematic of the Philadelphia Chromosome

Abl1 bound to Nilotinib

Philadelphia chromosome is a specific genetic abnormality in chromosome 22 of leukemia cancer cells. This abnormality was first discovered in the city of Philadelphia, Pennsylvania and is hence named after it.

Discovery

The Philadelphia chromosome was first discovered and described by David Hungerford from Fox Chase Cancer Center and Peter Nowell from the University of Pennsylvania School of Medicine in 1960. It was the first chromosomal abnormality to be associated with a specific disease, chronic myelogenous leukemia (CML).

Formation

The Philadelphia chromosome is formed through a process called translocation, where parts of two chromosomes (in this case, chromosome 9 and chromosome 22) swap places. This results in a longer chromosome 9 and a shorter chromosome 22, the latter being the Philadelphia chromosome.

Associated Diseases

The Philadelphia chromosome is most commonly associated with chronic myelogenous leukemia. It is also sometimes found in patients with acute lymphoblastic leukemia (ALL) and occasionally in patients with acute myelogenous leukemia (AML).

Treatment

The discovery of the Philadelphia chromosome led to the development of the first targeted cancer therapy, Imatinib (Gleevec). This drug specifically inhibits the BCR-ABL1 fusion protein that is produced by the Philadelphia chromosome.

See Also

• Chronic myelogenous leukemia
• Acute lymphoblastic leukemia
• Acute myelogenous leukemia
• Imatinib