Galectin-3 expression is associated with tumor progression and pattern of sun exposure in melanoma.
OBJECTIVE
Most studies accept a multistep pathogenic process in melanoma that may include the phases of benign nevi and dysplastic nevi, melanoma, and metastatic melanoma. Dysregulation of cellular proliferation and apoptosis is probably involved in melanoma progression and response to therapy. We have studied the expression of galectin-3, a beta-galactoside-binding protein involved in apoptosis, angiogenesis, and cell proliferation, in a large series of melanocytic lesions, and correlated the expression with clinical and histologic features.


METHODS
Tissue microarray blocks of 94 melanocytic lesions were semiquantitatively evaluated by immunohistochemistry for the cytoplasmic or nuclear expression of galectin-3.


RESULTS
Primary and metastatic melanomas expressed galectin-3 at a significantly higher level than nevi in both cytoplasm and nuclei (P<0.0073). There was a significant association between anatomic source (as indirect indication of level of sun-exposure) and cytoplasmic and nuclear expression. Lymph node and visceral metastases had a higher level of expression than s.c. lesions (P<0.004). Interestingly, there was an almost significant finding of worse survival in those patients with lesions showing higher levels of cytoplasmic than nuclear galectin-3 expression (log-rank test, P=0.06).


CONCLUSIONS
Melanocytes accumulate galectin-3 with tumor progression, particularly in the nucleus. The strong association of cytoplasmic and nuclear expression in lesions of sun-exposed areas suggests an involvement of UV light in activation of galectin-3.
Prieto
Victor G
VG
Department of Pathology, The University of Texas M.D. Anderson Cancer Center, The Methodist Hospital, Houston 77030, USA. vprieto@mdanderson.org
Mourad-Zeidan
Alexandra A
AA
Melnikova
Vladislava
V
Johnson
Marcella M
MM
Lopez
Adriana
A
Diwan
A Hafeez
AH
Lazar
Alexander J F
AJ
Shen
Steven S
SS
Zhang
Peter S
PS
Reed
Jon A
JA
Gershenwald
Jeffrey E
JE
Raz
Avraham
A
Bar-Eli
Menashe
M
D014408:Biomarkers, Tumor / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D018450:Disease Progression; D018572:Disease-Free Survival; D037502:Galectin 3 / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology; D008545:Melanoma / Q000209:etiology* / Q000378:metabolism* / Q000628:therapy; D009506:Nevus / Q000378:metabolism; D009508:Nevus, Pigmented / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000209:etiology* / Q000378:metabolism* / Q000628:therapy; D013472:Sunlight / Q000009:adverse effects*; D046888:Tissue Array Analysis
D014408:Biomarkers, Tumor; D037502:Galectin 3; D009687:Nuclear Proteins