Prognostic value of beta1 integrin expression in metastatic melanoma

The expression of integrin-type cell adhesion receptors is frequently changed in malignant transformation. Despite their important role in cancer cell behaviour, the value of integrins as prognostic markers is mostly unknown. We have examined the expression of beta1 integrins in 38 metastatic melanomas obtained from 27 patients treated with combined chemoimmunotherapy. On the basis of beta1 integrin expression, the melanoma samples were divided into two groups: beta1-negative tumours (<10% beta1 integrin immunostained cells) and beta1-positive tumours (with > or = 10% positive cells). Patients with beta1-positive tumours (n = 15) had significantly longer disease-free survival (median 38 versus 7 months, P < 0.0001) and overall survival (median 70 versus 23 months, P = 0.0001) evaluated after the diagnosis of primary disease compared with patients with beta1-negative metastases (n = 11). Moreover, the survival of the patients with beta1-positive tumours after the initiation of chemoimmunotherapy was significantly prolonged (median 18 versus 9 months, P = 0.017). The independent nature of beta1 integrin expression as a significant prognostic factor for survival after therapy was confirmed using Cox's multivariate analysis (P = 0.014). Our results indicate that the expression of beta1 integrins might have some major tumour growth regulatory role and can be used as a predictor for prognosis in patients with metastatic melanoma.