(A) AI-treated patients with high LMW primary tumors have increased frequency of recurrence (4/28, 14.3%) when compared to patients with low LMW tumors (3/100, 3.0%; Fisher’s exact test P=0.041). (B) Western blot analysis to measure CDK2 protein levels in breast cancer tissues from patients with high LMW cyclin E levels but did not relapse (n=4), from patients with high LMW cyclin E levels who relapsed (n=4), from patients with low LMW cyclin E levels but did not relapse (n=3), and from patients with low LMW cyclin E levels who relapsed (n=3). Lysates were subjected to western blot analysis (50 µg of protein) with CDK2 (D-12, sc-6248). Total cyclin E levels were determined by western blot analysis and densitometry was used to quantitate full length and LMW forms for each sample. The densitometric values of LMW cyclin E are presented in the bar graph. Units used are arbituary. (C) AI-resistant tumors have increased levels of CDK2. 6 out of 7 patients with recurrent disease had increased CDK2 protein levels compared to 1 out of 7 patients with no relapse (P= 0.0291, Fisher’s exact test).