There are other examples of oncoviruses including: Epstein-Barr virus and Human herpes virus 8 (Kaposi's Sarcoma).

Makes me wonder: Is the cancer "industry" searching for causes or just after-the-fact treatment?

There are billions of dollars spent on this problem through huge DNA/RNA/Epigenomics/Chromatin Accessibility sequencing initiatives. There is also a huge amount of model system work such as mouse models.