Immunological microenvironment in prostate cancer: high mast cell densities are associated with favorable tumor characteristics and good prognosis.
BACKGROUND
Number of intratumoral mast cells predicts survival in various cancers. The prognostic significance of such mast cells in surgically treated prostate cancer is unknown.


METHODS
Mast cell densities were determined in prostate cancer samples of more than 2,300 hormone-naïve patients using a tissue microarray format in correlation with clinical follow-up data. Mast cells were visualized immunohistochemically (c-kit). All patients were homogeneously treated by radical prostatectomy at a single institution.


RESULTS
Mast cells were present in 95.9% of the tumor samples. Median mast cell number on the tissue spot was 9 (range: 0-90; median density: 31 mast cells/mm(2)). High mast cell densities were significantly associated with more favorable tumors having lower preoperative prostate-specific antigen (P = 0.0021), Gleason score (P < 0.0001) and tumor stage (P < 0.0001) than tumors with low mast cell densities. Prostate-specific antigen recurrence-free survival significantly (P = 0.0001) decreased with decline of mast cell density showing poorest outcome for patients without intratumoral mast cells. In multivariate analysis mast cell density narrowly missed to add independent prognostic information (P = 0.0815) for prostate-specific antigen recurrence.


CONCLUSIONS
High intratumoral mast cell density is associated with favorable tumor characteristics and good prognosis in prostate cancer. This finding is consistent with a role of mast cells in the immunological host-defense reaction on prostate cancer. Triggering mast cell activity might expand immunotherapeutic strategies in prostate cancer.
Fleischmann
Achim
A
Department of Pathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. achim.fleischmann@pathology.unibe.ch
Schlomm
Thorsten
T
Köllermann
Jens
J
Sekulic
Nikolina
N
Huland
Hartwig
H
Mirlacher
Martina
M
Sauter
Guido
G
Simon
Ronald
R
Erbersdobler
Andreas
A
D000368:Aged; D002452:Cell Count; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000276:immunology* / Q000473:pathology* / Q000601:surgery; D040081:Protein Array Analysis; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D012307:Risk Factors
D019009:Proto-Oncogene Proteins c-kit; D017430:Prostate-Specific Antigen