In vitro monocyte maturation in patients with malignant melanoma and colorectal cancer--clinical significance.

In vitro monocyte maturation was studied in 52 malignant melanoma patients, 15 patients with colorectal cancer and 44 healthy donors. Index of maturation (IM) was in malignant melanoma patients 6.3 +/- 5.1%, in colorectal cancer 12.7 +/- 9.6%, and in healthy donors 40.4 +/- 18.0%. The difference between mean values in malignant melanoma patients and patients with colorectal cancer was significant when compared with healthy donors (p less than 0.001). The values in malignant melanoma patients decreased in accordance with stage of the disease and the difference between Stage I and Stage IV was significant (8.2 +/- 4.0% vs. 2.8 +/- 2.0%, p less than 0.01). In patients with colorectal cancer significant difference was established between operated patients and inoperable cases (21.4 +/- 10.0 vs. 5.1 +/- 1.9%, p less than 0.01). Monocyte maturation was influenced by the success of treatment. In patients with complete response the values were significantly higher than in patients with progression (11.7 +/- 6.7% vs. 2.2 +/- 1.5%, p less than 0.001). Autologous serum seems to inhibit the maturation process in vitro in cancer patients, while it apparently has no influence in healthy donors. When a response to treatment was achieved the previously low values of IM increased, while at progression a decrease was noted. The correlation between in vitro monocyte maturation and clinical factors leads to conclusion that the in vitro maturation reflects the in vivo process and may prove useful as a marker of tumor load or spread and may be a sensitive monitor of the treatment effect.