Melastatin expression and prognosis in cutaneous malignant melanoma.
OBJECTIVE
Melastatin (MLSN-1), a novel melanocyte-specific gene recently identified using a genomic approach, is expressed in murine and human melanoma cells at levels inversely proportional to metastatic rates in vivo. We studied the relationship between expression of melastatin mRNA in the primary cutaneous tumor and prognosis in patients with localized malignant melanoma.


METHODS
Melastatin mRNA was evaluated by in situ hybridization in primary cutaneous melanoma from 150 patients with localized disease (American Joint Committee on Cancer [AJCC] stage I and II). Multivariate Cox proportional hazards regression analysis was performed to assess the prognostic utility of melastatin mRNA expression while adjusting for other prognostic indicators.


RESULTS
Uniform melastatin mRNA expression in the primary tumor was correlated with prolonged disease-free survival (P < .0001). Multivariate analysis revealed that melastatin status, mitotic rate, and tumor thickness influence disease-free survival independently. The 8-year disease-free survival rate in AJCC stage I patients whose tumors diffusely expressed melastatin mRNA was 100%, whereas in stage I patients with melastatin loss, the disease-free survival rate was 77% +/- 15% (median +/- SE). In patients with stage II disease whose tumors diffusely expressed melastatin mRNA, the 8-year disease-free survival rate was 90% +/- 7%, whereas in patients with melastatin loss, the disease-free survival rate was 51% +/- 8%.


CONCLUSIONS
Downregulation of melastatin mRNA in the primary cutaneous tumor is a prognostic marker for metastasis in patients with localized malignant melanoma and is independent of tumor thickness and other variables. Used in combination, melastatin status and tumor thickness allow for the identification of subgroups of patients at high and low risk of developing metastatic disease.
Duncan
L M
LM
Dermatopathology Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA. ducan@helix.mgh.harvard.edu
Deeds
J
J
Cronin
F E
FE
Donovan
M
M
Sober
A J
AJ
Kauffman
M
M
McCarthy
J J
JJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D015536:Down-Regulation; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D015999:Multivariate Analysis; D009363:Neoplasm Proteins; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000032:analysis; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D016019:Survival Analysis; D050053:TRPM Cation Channels
D015415:Biomarkers; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D050053:TRPM Cation Channels; C492059:TRPM1 protein, human