Identification of glypican-3 as a novel tumor marker for melanoma.
OBJECTIVE
We reported recently the novel tumor marker glypican-3 (GPC3) for hepatocellular carcinoma. In the present study, we investigated the expression of GPC3 in human melanoma cell lines and tissues and asked whether GPC3 could be a novel tumor marker for melanoma.


METHODS
Expression of GPC3 mRNA and protein was investigated in human melanoma cell lines and tissues using reverse transcription-PCR and immunohistochemical analysis. Secreted GPC3 protein was quantified using ELISA in culture supernatants of melanoma cell lines and in sera from 91 patients with melanoma and 28 disease-free patients after surgical removal of primary melanoma. All of the subjects were Japanese nationals.


RESULTS
In >80% of melanoma and melanocytic nevus, there was evident expression of GPC3 mRNA and protein. Furthermore, GPC3 protein was evidenced in sera of 39.6% (36 of 91) of melanoma patients but not in sera from subjects with large congenital melanocytic nevus (0 of 5) and from healthy donors (0 of 60). Twenty-seven of 36 serum GPC3-positive patients were negative for both serum 5-S-cysteinyldopa and melanoma-inhibitory activity, well-known tumor markers for melanoma. The positive rate of serum GPC3 (39.6%) was significantly higher than that of 5-S-cysteinyldopa (26.7%) and of melanoma-inhibitory activity (20.9%). Surprisingly, we detected serum GPC3 even in patients with stage 0 in situ melanoma. The positive rate of serum GPC3 at stage 0, I, and II (44.4%, 40.0%, and 47.6%) was significantly higher than that of 5-S-cysteinyldopa (0.0%, 8.0%, and 10.0%). Also observed was the disappearance of GPC3 protein in sera from 11 patients after surgical removal of the melanoma.


CONCLUSIONS
GPC3 is apparently a novel tumor marker useful for the diagnosis of melanoma, especially in early stages of the disorder.
Department of Immunogenetics, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Tetsuya
T
Nakatsura
Toshiro
T
Kageshita
Shosuke
S
Ito
Kazumasa
K
Wakamatsu
Mikio
M
Monji
Yoshiaki
Y
Ikuta
Satoru
S
Senju
Tomomichi
T
Ono
Yasuharu
Y
Nishimura
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D053673:Glypicans; D019812:Heparan Sulfate Proteoglycans / Q000032:analysis* / Q000097:blood / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008875:Middle Aged; D041681:NIH 3T3 Cells; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D053673:Glypicans; D019812:Heparan Sulfate Proteoglycans; D012333:RNA, Messenger