On the road to precision, there is more practical medicine to be implemented

Estimates are that of the annual global burden of 1.5 million new cases of breast cancer, two-thirds have hormone receptor positive tumors; a majority of these women come from low- and middle-income countries. For adjuvant patients with hormone receptor positive tumors, a major goal is identification of a "precision medicine", implying a genomic, test whose application will allow identification of those whose systemic treatment can be hormonal therapy alone. Such tests in current use are very expensive and thus in the foreseeable future are out of reach of most women who pay out of pocket. For some time it has been evident that quantitative scoring of tumors for intensity and prevalence of tumor-cell staining for estrogen or progesterone receptor (ER or PR) expression (the commonest system was first described by Allred and thus provides "Allred" scores) gives an inexpensive measure of likelihood of response to hormonal therapies - a different predictive, precision medicine tool. Majorities of hormone receptor positive tumors (one third of all patients) have "Allred" scores of 6-8 (versus scores of 3-5) for both ER and PR and these tumor-bearing patients benefit significantly more from hormonal treatments than their lowering scoring-afflicted women. When ER and PR quantitative intensity and prevalence scoring is combined with Her-2/neu testing and careful tumor histologic grading, luminal A and B type tumors can be well-defined and gene-expression testing adds little practical predictive information. For women with hormone receptor positive tumors, high quality, cost-effective "precision medicine" is available without tumor gene-expression testing.