Change in % amount of PR in multiple tumors?

grrifff

I saw my doctor today. He mentioned that the primary tumor in my breast was 15% PR, the largest tumor in my axillary nodes was 60% PR and the tumor on my L1 was 90% PR. Why would this be? Has anyone else had multiple tumors biopsied with varying percentages of PR? All tumors were 90+% ER, Her2- He said it shows how estrogen fueled my cancer is. Thanks-Jil