Evaluation of genotoxic effects of treatments in breast cancer patients

CEBALLOS P; CAPITAINE FUNES, J; MASSA E; ZUMOFFEN, CARLOS M.; CAPITAINE FUNES, CARLOS; TOZZINI, ROBERTO; GHERSEVICH, SERGIO

Congreso; XII Congreso XXX Reunión Anual de la Sociedad de Biología de Rosario; 2010

This study evaluated the damage in lymphocytes’ DNA by the Comet assay(CA) in cells from healthy donors and patients with breast carcinoma,before (PRE) and after (POS) the first cycle of treatment. In addition, acutoff value for basal DNA damage in PRE was proposed in order to predictthe risk of more severe genotoxic damage due to treatments. Sampleswere obtained from patients with breast carcinoma (PRE = 54; POS = 24)and healthy donors (n = 15). For the CA, lymphocytes were separated byPercoll gradient, included in 1% agarose gels, and subjected to electrophoresisunder alkaline conditions. Comets were stained with ethidiumbromide and observed in a fluorescence microscope. The CASP programwas used to obtain % of DNA remaining at the head of comets (% DNA).For the visual analysis comets were classified into 5 types. Statistical analysiswas performed by the student’s t test. A value of p < 0,05 was consideredsignificant. The % DNA was significantly higher in PRE than in POSsamples (62.0 ± 2.6% vs. 38.9 ± 3.2%, respectively, p < 0.001). The differencebetween % DNA of samples from healthy donors and from patientsPRE was not statistically significant. Based on data from healthy donorsand samples PRE, a cutoff value for % DNA of 65% was considered toclassify the samples (% DNA < 65% or % DNA > 65%). Considering thisvalue, the PRE samples were divided into 2 groups and the averages of %DNA in POS samples from each group were significantly different (49.2 ±4.4% vs. 30.3 ± 3.1%, respectively, p < 0.01). The results support the usefulnessof the CA to monitor the genotoxic damage of the anti-tumor treatment.The CA could contribute to assess the type of treatment for eachpatient according to the level of initial damage in their DNA, to reduce theexcessive genotoxic damage.Partially financed by a grant from F. Fiorini Fundation.