Expression of the ALK protein by anaplastic large-cell lymphomas correlates with high proliferative activity.
A variable fraction of anaplastic large-cell lymphomas (ALCLs) exhibits a t(2;5)(p23;q35) translocation that results in expression of the chimeric hyperphosphorylated protein NPM-ALK (p80). Tumor cells expressing NPM-ALK exhibit markedly enhanced proliferative activity, but comparative cellular kinetic studies on ALK(+) (ALK lymphomas) and ALK(-) lymphomas are lacking. The present study showed that ALK(+) lymphomas, detected with the monoclonal antibody ALKc (n = 17), had significantly higher average values for the proliferation-associated parameters mitotic index, ana/telophase index, growth index (x x mitotic index - apoptotic index, assuming x = 3), percentages of Ki-67(+) cells and fraction of cells expressing cyclin A or B or the cell cycle-regulatory protein p34(cdc2) than did ALK(-) ALCLs (n = 15). Whether this intense proliferative activity contributes to the good response to chemotherapy and favorable outcome of ALK(+) ALCLs remains to be assessed in a larger series of patients. Our findings support the notion that ALK(+) and ALK(-) ALCLs are 2 distinct disease entities.
Leoncini
L
L
Institute of Pathology, University of Sassari, Sassari, Italy.
Lazzi
S
S
Scano
D
D
Mura
A
A
Onida
A
A
Massarelli
G
G
Tosi
P
P
Barbini
P
P
Cevenini
G
G
Massai
M R
MR
Pileri
S
S
Falini
B
B
Giordano
A
A
Kraft
R
R
Laissue
J A
JA
Cottier
H
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077548:Anaplastic Lymphoma Kinase; D002455:Cell Division; D002648:Child; D019925:Cyclin A / Q000032:analysis; D019926:Cyclin B / Q000032:analysis; D005260:Female; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D011505:Protein-Tyrosine Kinases / Q000032:analysis*; D020794:Receptor Protein-Tyrosine Kinases
D019925:Cyclin A; D019926:Cyclin B; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases