CD44 expression is a feature of prostatic small cell carcinoma and distinguishes it from its mimickers.
Small cell neuroendocrine carcinoma of the prostate is a rare variant of prostatic cancer that shares morphologic similarity with prostatic adenocarcinoma of Gleason 5 pattern. It has also been considered morphologically and immunohistochemically indistinguishable from small cell neuroendocrine carcinomas of other origins. CD44 is a cell-surface molecule proposed to identify cancer stem/progenitor cells in prostate cancer. We performed immunohistochemical study for CD44 expression in 11 cases of prostatic small cell neuroendocrine carcinoma and compared its patterns of expression with 73 cases of prostatic adenocarcinoma and 47 cases of small cell neuroendocrine carcinomas of other organs. Strong and diffuse membrane staining for CD44 was observed in 100% of the prostatic small cell neuroendocrine carcinomas. In conventional adenocarcinomas of the prostate, positive staining was only seen in rare, scattered tumor cells; and CD44 staining was negative in most of the small cell neuroendocrine carcinomas of nonprostate origin. The difference in CD44 expression between small cell neuroendocrine carcinomas of the prostate and those of other organs are statistically significant (P < .001). Our study demonstrates the utility of immunohistochemical staining for CD44 in distinguishing prostatic small cell neuroendocrine carcinoma from its mimickers including prostatic adenocarcinoma of Gleason 5 pattern and small cell neuroendocrine carcinomas of other organs. CD44 is the first marker that shows a high degree of tissue/organ specificity for small cell neuroendocrine carcinomas. Because CD44 is a putative marker of prostate cancer stem cells, the strong and diffuse expression of CD44 and the lack of expression of prostate luminal differentiation markers androgen receptor and prostatic specific antigen in prostatic small cell neuroendocrine carcinomas suggest that the tumor cells may retain cancer stem cell features.
Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642, USA.
Rochelle A
RA
Simon
P Anthony
PA
di Sant'Agnese
Li-Shan
LS
Huang
Haodong
H
Xu
Jorge L
JL
Yao
Qi
Q
Yang
Sharon
S
Liang
Jinsong
J
Liu
Rena
R
Yu
Liang
L
Cheng
William K
WK
Oh
Ganesh S
GS
Palapattu
Jianjun
J
Wei
Jiaoti
J
Huang
D000230:Adenocarcinoma / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis*; D018278:Carcinoma, Neuroendocrine / Q000473:pathology; D018288:Carcinoma, Small Cell / Q000378:metabolism / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis*; D007150:Immunohistochemistry; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D046888:Tissue Array Analysis
D014408:Biomarkers, Tumor; D018960:Hyaluronan Receptors