Method for predicting breast cancer patient response to endocrine therapy

A method of determining whether a hormone receptor positive breast cancer patient, regardless of HER2 status, is unlikely to benefit from administration of an endocrine therapy drug alone for treatment of the cancer, comprising the steps of:

• a) conducting mass spectrometry on a blood-based sample from the patient with a mass-spectrometer and thereby obtaining a mass spectrum of the blood-based sample wherein the patient is HER positive or HER negative;
• and, with the aid of a programmed computer:
• b) performing one or more predefined pre-processing steps on the mass spectrum obtained in step a);
• c) obtaining integrated intensity values of selected features in said mass spectrum at one or more predefined m/z ranges after the pre-processing steps on the mass spectrum in step b) have been performed;
• wherein the one or more predefined m/z ranges comprises one or more m/z ranges selected from the group of m/z ranges consisting of:
• 5732 to 5795
• 5811 to 5875
• 6398 to 6469
• 11376 to 11515
• 11459 to 11599
• 11614 to 11756
• 11687 to 11831
• 11830 to 11976
• 12375 to 12529
• 23183 to 23525
• 23279 to 23622 and
• 65902 to 67502;
• d) wherein the programmed computer comprises a stored set of class-labeled mass spectral data from blood-based samples from other treated solid epithelial tumor cancer patients, executing in the programmed computer a classification algorithm comparing the integrated intensity values obtained in step c) to features in the stored set of mass spectral data to thereby obtain a class label for the sample;
• and
• e) if the class label for the sample obtained by the classification algorithm in step d) is “Poor” or the equivalent, then the patient is identified as being unlikely to benefit from the endocrine therapy drug.