When I first learned I had invasive breast cancer, I assumed the treatment would consist of some combination of surgery, chemotherapy and/or radiation. I knew that cancers had stages but was unaware of "grades" as well. Reading the biopsy report and seeing mention of Grade 3 and a Ki-67 of 50% rudely introduced me to the biological aspects of the cancer cells themselves. With a grade 3 and Ki-67 of 50%, I considered my cancer, though staged as !C, to be aggressive. A relatively high Oncotype DX score added to that conclusion and chemotherapy was added.

My oncologist, however, does not really get into any detail in answering my questions about Ki-67, e.g., what exactly is it? If is a gene? A protein? I'm not how widely the test is even used when doing biopsies. I've also read that different labs can reach different measurements. In my own case, my initial biopsy showed a 50% level of Ki-67 but the biopsy done during my actual double mastectomy came back with 30% which is still high, though lower.

Based on my diagnosis, I think my oncologist may be recommending not only an AI but also a CDK-inhibitor. I think CDK inhibitors may initially have been recommended for metastatic breast cancer, but now seem to have broadened in their use to include higher Ki-67 levels.

I've found articles about Ki-67 but don't get into their details. I know that the my 3 biological markers (grade, Ki-67, and Oncotype) suggest my cancer cells are aggressive.

I should mention that when you get the Oncotype DX results, you are given a basic number but no breakdown of the actual genes which are tested. I had a genetic test done prior to my breast cancer diagnosis and tested negative for the BRCA genes and any other genes associated with breast cancer. I'm curious what those other genes could be that were picked up by the Oncotype DX test.