Common ALK gene rearrangement in Asian CD30+ anaplastic large cell lymphoma: an immunohistochemical and fluorescence in situ hybridisation (FISH) study on paraffin-embedded tissue.
OBJECTIVE
The most common recurrent genetic aberration in anaplastic large cell lymphoma (ALCL) is translocation involving the ALK gene that results in ectopic expression of ALK protein in lymphoid tissue. This study aims to investigate the frequency of ALK gene rearrangement in a series of Asian ALCL.


METHODS
ALK gene rearrangement was detected by immunostaining of ALK protein and fluorescence in situ hybridisation (FISH) targeting at the 2p23 region.


RESULTS
The expression of ALK protein was detected in 24/34 (71%) of the cases, and it was significantly higher in childhood cases (100%) when compared to adult cases (47%). The analyses by FISH were consistent with the results from immunostaining of ALK protein, but the analyses were only successful in 15/34 (44%) cases. FISH analyses detected extra copies of ALK gene in three cases, including one case that expressed ALK protein and showed 2p23 rearrangement.


CONCLUSIONS
The current series revealed a high frequency of ALK gene rearrangement, especially in the children. Immunostaining of ALK protein is a reliable indication of ALK gene rearrangement, and is superior to FISH. However, FISH analysis is useful in detecting other genetic aberrations that are not related to ALK gene rearrangement.
Tai
Yan Chin
YC
Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Kim
Lian Hua
LH
Peh
Suat Cheng
SC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000077548:Anaplastic Lymphoma Kinase; D002648:Child; D002675:Child, Preschool; D002889:Chromosomes, Human, Pair 2; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D017730:Ki-1 Antigen / Q000378:metabolism; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016612:Paraffin Embedding; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases; D014178:Translocation, Genetic
D017730:Ki-1 Antigen; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases