Tumor-stage-specific markers

An ideal tumor marker would be a molecule specific to one type of tumor (100% specificity, i.e. no false positives) and detectable right from the initial stage of the disease (100% sensitivity, i.e. no false negatives). It would be undetectable in healthy subjects, and enable the screening and diagnosis of cancer. The tumor marker level should correlate closely with tumor size, contribute to the initial extension of the profile and evaluation of therapeutic efficacy, as well as the early detection of recurrent diseases. 

As for malignant melanoma, more than 15 study groups have attempted to detect circulating tumor cells using conventional RT-PCR for melanocyte-specific markers, mainly tyrosinase as well as MART -1. Many studies showed a correlation between the detection of tyrosinase RT-PCR positive cells in the peripheral blood and the clinical stage (B4), but not all of the studies (R2). In patients with stage 0, 15 to 30% of the patients were tyrosinase... 

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