Immunocytochemical detection of hMSH2 and hMLH1 expression in oral melanoma.
BACKGROUND
The DNA mismatch repair system (MMR) plays an important role in the maintenance of genomic stability. To date few studies have been performed on hMSH2 and hMLH1 expression and melanoma of the head and neck region. A study of two cases revealed no mutations of the mismatch repair genes hMSH2 and hMLH1.


METHODS
To verify the possibility of implication of hMSH2 and hMLH1 alterations in melanocytic cancerogenesis, the authors examined the protein expression pattern of hMSH2 and hMLH1 by immunohistochemistry in 9 paraffin-embedded oral melanoma.


RESULTS
One case (11%) showed nuclear positivity for hMSH2, 3 cases (33%) showed cytoplasmic positivity, and five cases (55%) showed no staining in the tumoral cells, even if normal squamous epithelium available in this section showed a nuclear positivity. Four cases (44%) showed no hMLH1 staining in the tumoral cells, even if normal squamous epithelium available in this section showed a nuclear positivity. Two cases (22%) showed nuclear positivity, and three cases (33%) showed cytoplasmic positivity.


CONCLUSIONS
The analysis of mismatch repair genes can be a new molecular diagnostic tools for the detection of patients at high risk of developing melanoma and other neoplasia, or metastasis and recurrences.
Lo Muzio
L
L
Department of Oral Medicine and Pathology, University of Naples Federico II, Faculty of Medicine and Surgery, Italy. lomuziol@tin.it
Nocini
P
P
Mignogna
M D
MD
Pannone
G
G
Staibano
S
S
Procaccini
M
M
Rubini
C
C
Fioroni
M
M
Fanali
S
S
Piattelli
A
A
D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D020137:Base Pair Mismatch; D002352:Carrier Proteins; D002467:Cell Nucleus / Q000473:pathology; D003593:Cytoplasm / Q000473:pathology; D004260:DNA Repair; D004268:DNA-Binding Proteins; D005260:Female; D005887:Gingival Neoplasms / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008048:Lip Neoplasms / Q000473:pathology; D008297:Male; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000473:pathology* / Q000556:secondary; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology; D009062:Mouth Neoplasms / Q000473:pathology*; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000032:analysis*; D009687:Nuclear Proteins; D010157:Palatal Neoplasms / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000032:analysis*
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein