Figure 1.

Increased OPN-ICOSL interaction in primary and its paired metastatic human melanoma. (A) Proximity Ligation Assay (PLA) in primary tumor and corresponding metastasis. The merged PLA signal (violet) shows ICOSL and OPN interaction, while nuclei are labeled with DAPI (blue). Images were quantified using ImageJ software in order to calculate the ratio between red (OPN) and green (ICOSL) channels; values are shown as percentage of red–green co-staining. Scale bar 50 μm. Four images were analyzed for each sample at a magnification of 40×. (B) The histograms quantify OPN-ICOSL PLA in signals of primary and metastatic tumors, expressed as MFI (mean ± SEM). Mann–Whitney statistical test was used, *** p < 0.001.