RATIONALE: Studying samples of blood from patients treated with sargramostim in the laboratory may help doctors learn more about the effects of sargramostim on cells. It may also help doctors understand how patients respond to treatment.

PURPOSE: This research trial studies biomarkers in blood samples from patients with stage IV melanoma previously treated with sargramostim.

OBJECTIVES:

Primary

• To correlate circulating myeloid-derived suppressor cells (MDSC) and Treg frequencies with clinical outcome.

Secondary

• To correlate circulating anti-sargramostim (GM-CSF) antibody levels with clinical outcome.

OUTLINE: Archived peripheral blood mononuclear cells and serum samples are analyzed for circulating myeloid-derived suppressor cells, Treg (CD3+/CD4+/CD25hi/FOXP3+) frequency, and anti-sargramostim (anti-GM-CSF) antibody levels by flow cytometry and anti-GM-CSF neutralizing antibody assay.

DISEASE CHARACTERISTICS:

• Diagnosed with melanoma

  • Stage IV disease
  • HLA-A2^+ and A2^+

• Received sargramostim on clinical trial ECOG-4697

• Specimens collected at baseline and either day 43 or day 85 (based on most consistent availability) from long-term survivors and patients with poor survival

PATIENT CHARACTERISTICS:

• Not specified

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

Samples from patient enrolled on E4697 from whom samples were submitted for research