Nck expression in human melanoma cell lines at different stages of cancer progression. Equivalent amount of total proteins from human primary and metastatic melanoma cell lysates (30 μg) were subjected to western blot analysis using indicated antibodies. (A) Pan-Nck antibodies recognize Nck1 and Nck2. eIF2α was used as loading control. (B) Nck1 and Nck2 are specific Nck isotypes antibodies (Additional file 1) and β-actin or tubulin was detected as loading controls. Quantification of Nck1 and Nck2 signals, evaluated in the linear range of detection by densitometry, are reported below the blots. Human Melanoma Cell Lines Characteristics: FW2294: normal melanocyte; WM115: poorly metastatic primary melanoma in vertical growth phase and with round morphology; WM164: elongated metastatic melanoma isolated from lymph nodes; WM278: poorly metastatic primary melanoma in vertical growth phase and with mixed morphology; WM1617: elongated metastatic melanoma derived from lymph nodes, sister match of WM278; 451Lu: elongated metastatic melanoma selected in lungs of mice injected with WM164 cells; 1205Lu: round metastatic melanoma selected in mice; WM1232: round metastatic melanoma.