Testing the simple micronucleus test to detect chromosomal breakage in peripheral blood mononuclear cells of patients receiving chemotherapy

Background: Chromosomal breakage can be detected by simple micronucleus (MN) test. However, It is supposed that simple MN test only detect chromosomal breakage caused by chronic clastogen exposure (e.g. smoking), as micronucleus is formed only after the cell proliferates. Objective: To assess the efficacy of simple MN test in individuals exposed to clastogens at various time after exposure, in an effort to know the time when this simple method will be effective. Design: Laboratory research. Setting: Dept. of Obstetrics and gynecology, Department of Pathology, and Department of Histology, Faculty of medicine, University of Indonesia, Jakarta. Samples: Heparinized blood samples that were taken some time after chemotherapy. There were 3 categories of samples: less than 1 month (A), 1-3 months (B), and 3-6 months (C) after chemotherapy. Procedures: Simple MN test. Main outcome measures: Number of cells containing micronucleus/cells screened. Results: Among the 35 samples 88.75% showed positive results (increased MN). Furthermore, in group A, B, and C, positive result was 93.33%, 100%, and 57.14%, respectively. Conclusion: Increase in cells with MN seemed to begin around 3 weeks after chemotherapy, the effect was increased between 1-3 moths after chemotherapy, but 3 months or more after chemotherapy, the effect was negated, possibly by impaired immune response.