title: The effect of laser irradiation on proliferation of human breast carcinoma, melanoma, and immortalized mammary epithelial cells.
abstract: OBJECTIVE
  This study compared the effects of different doses (J/cm(2)) of laser phototherapy at wavelengths of either 780, 830, or 904 nm on human breast carcinoma, melanoma, and immortalized human mammary epithelial cell lines in vitro. In addition, we examined whether laser irradiation would malignantly transform the murine fibroblast NIH3T3 cell line.
  
  
  BACKGROUND
  Laser phototherapy is used in the clinical treatment of breast cancer-related lymphoedema, despite limited safety information. This study contributes to systematically developing guidelines for the safe use of laser in breast cancer-related lymphoedema.
  
  
  METHODS
  Human breast adenocarcinoma (MCF-7), human breast ductal carcinoma with melanomic genotypic traits (MDA-MB-435S), and immortalized human mammary epithelial (SVCT and Bre80hTERT) cell lines were irradiated with a single exposure of laser. MCF-7 cells were further irradiated with two and three exposures of each laser wavelength. Cell proliferation was assessed 24 h after irradiation.
  
  
  RESULTS
  Although certain doses of laser increased MCF-7 cell proliferation, multiple exposures had either no effect or showed negative dose response relationships. No sign of malignant transformation of cells by laser phototherapy was detected under the conditions applied here.
  
  
  CONCLUSIONS
  Before a definitive conclusion can be made regarding the safety of laser for breast cancer-related lymphoedema, further in vivo research is required.
authors.affiliation: School of Medical Science, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Katie
authors.initials: K
authors.lastname: Powell
authors.forename: Pauline
authors.initials: P
authors.lastname: Low
authors.forename: P Ann
authors.initials: PA
authors.lastname: McDonnell
authors.forename: E-Liisa
authors.initials: EL
authors.lastname: Laakso
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Ralph
mesh_terms: D000230:Adenocarcinoma / Q000532:radiotherapy*; D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000532:radiotherapy*; D018270:Carcinoma, Ductal, Breast / Q000532:radiotherapy*; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000528:radiation effects*; D002471:Cell Transformation, Neoplastic; D004307:Dose-Response Relationship, Radiation; D004847:Epithelial Cells / Q000528:radiation effects*; D006801:Humans; D054023:Lasers, Semiconductor; D016014:Linear Models; D028022:Low-Level Light Therapy / Q000379:methods*; D008545:Melanoma / Q000532:radiotherapy*; D014162:Transfection