Study of Blood Samples From Patients With Malignant Melanoma, Metastatic Breast Cancer, Advanced Lung Cancer, Pancreatic Cancer, or Colorectal Cancer.

OBJECTIVES: Primary * To assess which potential peptide and protein markers produced by human melanoma, lung, breast, pancreatic, and colorectal cell lines may be detectable in serum of patients from these five disease groups. Secondary * To conduct further extensive investigation with respect to identification of the protein/peptide involved, determination of specificity for each cancer, and development of more sensitive assays to look for such markers in a wider population of patients, including those undergoing therapy. OUTLINE: This is a multicenter study. Blood samples are collected before surgical intervention or treatment to assess peptide and protein markers.