β1 integrin expression: A marker of lymphatic metastases in cutaneous malignant melanoma

Background: Experimental evidence suggests that integrins are key regulators of the development of melanoma metastases, influencing both the likelihood and site of metastases. Whereas effective treatment of cutaneous melanoma remains surgical, elective lymph node dissection (ELND) is controversial. the present study was designed to investigate the relationship between integrin expression by a given primary melanoma and occult regional lymph node metastases. Materials and Methods: We studied β1 integrin expression by quantitative immunohistochemistry using an image analyzer, in the primary melanomas of 90 ELND patients. Results: β1 integrin was expressed in ≤ 10% of the primary tumor in 92% of cases with lymph node involvement versus 9% of node negative cases (p < 0.001). Conclusions: Our data demonstrate that quantitative immunohistochemistry for β1 integrin expression in primary melanomas can identify patients likely to have occult lymph node metastases. This suggests that β1 integrins play a role in the lymphatic dissemination of cutaneous melanoma.