The prevalence and clinical implications of c-kit expression in plasma cell myeloma.
OBJECTIVE
To evaluate the clinical implications of c-kit (CD117) expression in plasma cell myeloma (PCM).


RESULTS
We first evaluated the reliability of immunohistochemistry in assessing c-kit expression by comparing the results with those obtained by flow cytometry and gene expression arrays in 22 PCM and in 10 PCM cell lines. Immunohistochemical results showed a perfect concordance with those of flow cytometry; likewise, immunohistochemical and gene expression data were also concordant in all but one PCM and cell lines analysed. Then, we investigated the clinical implications of c-kit immunoreactivity in bone marrow biopsies of 85 PCM patients with a mean follow-up of 41 months. C-kit immunoreactivity was detected in 24 (28.2%) of the 85 cases and it was significantly associated with a high microvessel density, but not with traditional clinicopathological characteristics or with survival.


CONCLUSIONS
Our findings suggest that immunohistochemistry is a reliable indicator of c-kit gene expression and reinforce the notion that approximately one-third of PCM express high levels of c-kit. The lack of association with traditional clinicopathological parameters and patient survival suggests that c-kit expression may not be an adjunct in predicting the clinical course of the disease.
Pruneri
G
G
Division of Pathology and Laboratory Medicine, European Institute of Oncology and University of Milan, School of Medicine, Italy. giancarlo.pruneri@ieo.it
Ponzoni
M
M
Ferreri
A J M
AJ
Freschi
M
M
Tresoldi
M
M
Baldini
L
L
Mattioli
M
M
Agnelli
L
L
Govi
S
S
Mancuso
P
P
Agazzi
A
A
Bertolini
F
F
Peccatori
J
J
Bosari
S
S
Gianelli
U
U
Viale
G
G
Neri
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D045744:Cell Line, Tumor; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D008875:Middle Aged; D009101:Multiple Myeloma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D011509:Proteoglycans / Q000032:analysis; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis* / Q000235:genetics; D016019:Survival Analysis; D053667:Syndecans
D008562:Membrane Glycoproteins; D011509:Proteoglycans; D053667:Syndecans; D019009:Proto-Oncogene Proteins c-kit