This may explain why using Tamoxifen for glioblastomas helped some patients. An old research paper (see https://virtualtrials.com/Tam1.cfm) from 1996 showed pretty good results using high dose tamoxifen for recurrent glioblastomas.
I had a relative who did well with high dose tamoxifen for over 5 years with her GBM, but it's use fell out of favor when Temodar arrived on the scene. Maybe it is time to go back and test this again in new combinations!