Post-treatment breast cancer prognosis

A method comprising:

• preparing cDNA from nucleic acids in a sample of ER+ breast cancer cells from a breast cancer afflicted subject,
• determining the expression levels of the seven genes in the disclosed Breast Cancer Index (BCI) from said cDNA, wherein said genes are HoxB13, IL17BR, Bub1B, CENPA, NEK2, RACGAP1, and RRM2, to determine a BCI value,
• identifying the subject as having undergone removal of the breast cancer and as having been treated with endocrine therapy for a period of time without cancer recurrence, and
• classifying the cancer as likely to recur due to a high risk BCI value.

A method to treat a cancer patient, said method comprising

• preparing cDNA from nucleic acids in a sample of ER+ breast cancer cells from a breast cancer afflicted subject,
• determining the expression level of the HoxB13 gene from said cDNA,
• identifying the subject as having undergone removal of the breast cancer and as having been treated with a first endocrine therapy for a period of time without cancer recurrence,
• classifying the subject as expected to benefit from treatment with the same first endocrine therapy or a different second endocrine therapy after cessation of the first endocrine therapy, wherein said classifying is based upon an elevated expression level of HoxB13, and
• treating the patient with the second endocrine therapy after ending treatment with the first endocrine therapy.