Systems and methods for determining whether a cancer patient may respond to inhibition of RNA polymerase II as a treatment for the patient are provided. Inhibition of RNA polymerase II may be by way of chemotherapy with an agent such as triptolide, an analog of triptolide, or a prodrug form of triptolide. The cancer patient may be a pancreatic cancer patient, an ovarian cancer patient, a gastric cancer patient, or an esophageal cancer patient. The patient may have any cancer in which c-Myc is over-expressed or over-amplified.