I recommend the Human Protein Altas (HPA) database which is visualized on its website.
If you search one specifc gene into HPA, the website could show the RNA expression level of the gene in various cancer cell line And different types of cancer. Moreover, the website (the Pathology category) also showed the Protein expression level (IHC) In different types of cancer (Human Cancer tissues). In addition, the website also show the cellular location of the gene you input.