Lymphatic density predicts melanoma metastasis

Lymphatic density (LD) and tumor cell invasion of lymphatics are strongly associated with metastatic spread from malignant melanoma, according to UK researchers.

The findings, which are reported in the February 9th issue of the British Journal of Cancer, are based on a histologic comparison of 22 melanoma samples, 11 normal dermis specimens, 6 basal cell cancer specimens, and 6 Merkel cell carcinoma samples. LD was determined by staining with a special lymphatic specific marker.Dr. David O. Bates, from the University of Bristol and colleagues found that LD was significantly increased around melanoma samples compared with the other specimen types. LD inside melanoma samples was significantly greater than that seen inside basal cell and Merkel cell cancer specimens, but similar to that of normal dermis. As noted, epitumoral LD was greater in melanomas that subsequently metastasized than in non-metastatic tumors (p < 0.001). Similarly, tumor cell invasion of lymphatics was seen in 70% of melanomas that metastasized, compared with just 12% of tumors that did not spread. The increased LD seen with metastatic melanomas, say the investigators "is probably brought about by lymphangiogenesis, which in turn supports the dissemination of cancer cells into the lymphatic system." "A larger scale study of LD around malignant melanoma," they add, "might be of value to determine the relative risk of metastasis with increased LD."(Source: Br J Cancer 2004;90:693-700: Reuters Health: February 24, 2004: Oncolink)