RT Journal Article SR Electronic T1 Role of chromosomal instability and clonal heterogeneity in the therapy response of breast cancer cell lines JF Cancer Biology and Medicine JO Cancer Biol Med FD China Anti-Cancer Association SP 970 OP 985 DO 10.20892/j.issn.2095-3941.2020.0028 VO 17 IS 4 A1 Vargas-Rondón, Natalia A1 Pérez-Mora, Erika A1 Villegas, Victoria E. A1 Rondón-Lagos, Milena YR 2020 UL http://www.cancerbiomed.org/content/17/4/970.abstract AB Objective Chromosomal instability (CIN) is a hallmark of cancer characterized by cell-to-cell variability in the number or structure of chromosomes, frequently observed in cancer cell populations and is associated with poor prognosis, metastasis, and therapeutic resistance. Breast cancer (BC) is characterized by unstable karyotypes and recent reports have indicated that CIN may influence the response of BC to chemotherapy regimens. However, paradoxical associations between extreme CIN and improved outcome have been observed.Methods This study aimed to 1) evaluate CIN levels and clonal heterogeneity (CH) in MCF7, ZR-751, MDA-MB468, BT474, and KPL4 BC cells treated with low doses of tamoxifen (TAM), docetaxel (DOC), doxorubicin (DOX), Herceptin (HT), and combined treatments (TAM/DOC, TAM/DOX, TAM/HT, HT/DOC, and HT/DOX) by using fluorescence in situ hybridization (FISH), and 2) examine the association with response to treatments by comparing FISH results with cell proliferation.Results Intermediate CIN was linked to drug sensitivity according to three characteristics: estrogen receptor α (ERα) and HER2 status, pre-existing CIN level in cancer cells, and the CIN induced by the treatments. ERα+/HER2− cells with intermediate CIN were sensitive to treatment with taxanes (DOC) and anthracyclines (DOX), while ERα−/HER2−, ERα+/HER2+, and ERα-/HER2+ cells with intermediate CIN were resistant to these treatments.Conclusions A greater understanding of CIN and CH in BC could assist in the optimization of existing therapeutic regimens and/or in supporting new strategies to improve cancer outcomes.