ET Jak2 mutation and endometrial cancer? correlation or causation?

That's tough, 1995victoria. Unfortunately, having one cancer may indicate we're susceptible to other cancers too. My sister (who doesn't have ET) has had both thyroid and breast cancer.

I'm so sorry you're facing this second challenge.

Do you like and trust the oncologist who will help with your endometrial cancer treatment?

While it doesn't help you one bit to hear it, the odds of getting another cancer are pretty low. But it's good to be aware of the possibility.

Below is a portion of the Conclusion section from "Risk of secondary malignancies in patients with MPN" from MPNHub, December 2020.

"Age is another factor that modifies the cancer risk uniformly across studies, with the largest elevated risk increase seen for patients between 60 and 79 years. Detection bias, due to routine surveillance of patients with MPN may have influenced these results to some degree. However, as the incidence of major cancer types, such as colorectal cancer, breast cancer, and prostate cancer, were not increased among patients with MPN, detection bias is unlikely to explain the observed increased risks in specific cancer types, such as lymphoid malignancies. Although cancer surveillance among all patients with MPN may be unnecessary, it may be beneficial for those at increased risk, such as the 60–70 age group."

In "Evaluating Risk of Developing Second Cancers in Patients . . . with MPNs" from ASH Clinical News, August 2019, I found this:

"Single-agent hydroxyurea treatment did not appear to increase the risk of any secondary cancer . . . ."