Evaluation of 2-methoxyestradiol serum levels as a potential prognostic marker in malignant melanoma

Abstract

Experimental findings indicated that 2-methoxyestradiol (2-ME), an endogenous metabolite of 17β-estradiol, may exhibit anti-tumorigenic properties in various types of tumour, such as melanoma and endometrial carcinoma. In patients with endometrial cancer, the serum levels of 2-ME are decreased compared with those in healthy controls, and this finding has been associated with a poor outcome. The aim of the present study was to examine whether the serum levels of 2-ME are decreased in patients with melanoma, and whether this decrease may be correlated with disease stage and, therefore, serve as a prognostic indicator. ELISA was used to detect serum levels of 2-ME in patients with stage I-IV malignant melanoma (MM). A cohort of 78 patients with MM was analysed, along with 25 healthy controls, among whom 15 were women in the second trimester of pregnancy (positive control). As expected, significantly elevated levels of serum 2-ME were observed in pregnant control patients compared with those in patients with MM and healthy controls. There was no observed correlation between 2-ME serum levels in patients with MM and disease stage, tumour thickness, lactate dehydrogenase or S100 calcium-binding protein B levels. In addition, the 2-ME levels of patients with MM did not differ significantly from those of normal healthy controls. Overall, the findings of the present study indicated that the 2-ME serum levels in patients with MM were not decreased, and there was no correlation with early- or advanced-stage disease. Therefore, in contrast to published results on endometrial cancer, endogenous serum 2-ME levels in MM were not found to be correlated with tumour stage and did not appear to be a suitable prognostic factor in MM.

Keywords: 2-methoxyestradiol; S100 calcium-binding protein B; lactate dehydrogenase; melanoma; prognostic factor; stage.

Figure 1

Measurement of 2-ME serum levels in pregnant controls (n=15), non-pregnant controls (n=10) and patients with malignant melanoma (n=78). The central box indicates the upper and lower percentiles (from P₂₅ to P₇₅), whereas the middle line represents the median. The upper and lower horizontal bars extend from the minimum to the maximum value; outliers are indicated by black dots. ^*P<0.05. 2-ME, 2-methoxyestradiol.