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Slow-Cycling ER-Positive Cells Linked to Late Breast Cancer Relapse

The study points to Rac1 signaling as a drug target to clear residual disease.

Overview

  • The Nature Communications study, published Monday, reports that some estrogen receptor-positive breast cancer cells persist by dividing at an ultra-slow rate through years of hormone therapy.
  • These slow-cycling cells can seed tiny, hidden tumors that later trigger metastatic relapse after standard treatment.
  • In preclinical tests, the cells still migrated and colonized organs such as bone and lung despite their slow growth.
  • Researchers traced this state to increased P-Rex1/Rac1 signaling and used biosensor imaging to see Rac1 switch on inside live cells.
  • Experimental Rac1 inhibitors reduced tumor size and number in patient-derived models, and the Caldon Lab plans studies to test preventive use in patients.