This technique is coming into prominence but genomic is still a very young science with the cost of sequencing only recently coming down enough to have it become regular practice. What we have now are essentially a shortlist of known mutations that are seen across many cancers, a huge list of closely associated mutations in the same pathway or impinging pathways that are sometimes seen in conjunction with other mutations, sometimes not and then a ton of noise from which researchers are trying to pick out possible correlation. The vast majority of mutations are not cancer causing, so picking out the ones that are is difficult. That being said, frequently broad characterization can be done. This person has an effected PI3Kinase, or MAP pathway. We only have drugs for a few of the major mutations so once the cancer mutates to avoid drugging, patients are often out of luck.

To answer your second question, cancer is generally accepted as a genetic disease ie mutations, copy number alterations, insertion and deletion of genetic information, however, recent research has shown that epigenetic processes (that is what your cells are doing with your genes such as alternative splicing or DNA methylation) are also an important factor and these can be effected by environmental factors such as diet, exercise, even mood.