c-myc is not useful as prognostic immunohistochemical marker in cutaneous melanoma.
BACKGROUND
Several studies indicate that immunohistochemical detection of the c-myc oncogene might serve as an additional prognostic marker in malignant melanoma.


OBJECTIVE
To study c-myc expression in paraffin-embedded cutaneous melanoma and to correlate to metastatic potential and onset of metastases.


METHODS
Cytoplasmic c-myc protein expression was visualized using the APAPP method, and reactivity (percent total tumor cells stained) was assessed in 62 formalin-fixed paraffin-embedded primary cutaneous melanomas (21 not metastasizing, mean Breslow 3.0 +/- 2.9 mm, 41 metastasizing, mean Breslow 3.1 +/- 3.0 mm) and 24 metastases of the same patients.


RESULTS
There was no significant difference of c-myc reactivity in cutaneous melanoma who did not metastasize (n = 21, c-myc reactivity 32.7 +/- 19.3%, follow-up 10.6 +/- 1.8 years) and primaries who metastasized (n = 41, c-myc reactivity 27.7 +/- 22.4%, p = 0.29). This finding was independent of the thickness of the primary and was found within thin cutaneous melanoma with a Breslow, < 0.75 mm (range 0.24-0.65 mm, n = 20, c-myc reactivity 29.1 +/- 15.7%, p = 0.32) or within thick cutaneous melanoma with a Breslow > 1.5 mm (range 1.6-11 mm, n = 41, c-myc reactivity 29.6 +/- 23.8%, p = 0.46). No correlation of c-myc expression between thin cutaneous melanoma, thick cutaneous melanoma (p = 0.83) or metastasizing primaries and their metastases (n = 24, c-myc reactivity 29.3 +/- 22%) was found (p = 0.64). The time period until development of first metastasis did not correlate with the percentage of cells expressing c-myc in the primary (p = 0.56).


CONCLUSIONS
c-myc expression is independent of metastatic potential and onset of metastases and, therefore, does not serve as a prognostic immunohistochemical marker in primary cutaneous melanoma.
Böni
R
R
Department of Dermatology, University Hospital, Zurich, Switzerland.
Bantschapp
O
O
Müller
B
B
Burg
G
G
D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000737:chemistry / Q000473:pathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D016271:Proto-Oncogene Proteins c-myc / Q000032:analysis*; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology*
D014408:Biomarkers, Tumor; D016271:Proto-Oncogene Proteins c-myc