Chatterjee S, et al. - Researchers intended to gain insight into the molecular basis of the survival benefit impact of hydroxyprogesterone on primary breast tumors in a peri-operative setting. Given it has already been reported that a single injection of hydroxyprogesterone, when administered prior to surgery for primary tumor in patients with node-positive operable breast cancer, resulted in a survival benefit. They collected primary breast tumor samples from patients before and after hydroxyprogesterone exposure and controls, to perform whole transcriptome sequencing (RNA-Seq). They found that the observed favorable modulation of the impact of surgical stress by pre-operative progesterone exposure might underlie its beneficial effect when administered prior to surgery.