Look here (https://cptac-data-portal.georgetown.edu/cptacPublic/) or here (http://www.proteinatlas.org/about/download) or here (http://bioinfo.vanderbilt.edu/canprovar/).
Thanks for sharing the information. I am interested in melanoma and prostate cancer patient samples. I found useful data about protein expression of different gene in www.proteinatlas.org suggested by Martin.