In the cytokinesis-block micronucleus (CBMN) assay, micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear budding (NBUD) are the most commonly analysed morphological types of nuclear abnormalities. In contrast, tailed and dumbbell-shaped nucleus have historically received little attention in the CBMN assay. Interestingly, the incidence of tailed and dumbbell-shaped nuclei in lymphocytes is closely related with that of dicentric chromosomes or NPBs in the CBMN assay. To provide a better picture of the implications and significance of tailed and dumbbell-shaped nuclei as markers of radiation exposure, a literature review was performed in this study. Twenty articles were found in PubMed, PubMed Central, and manually searched. The articles were screened and those that met the inclusion criteria and did not meet the exclusion criteria were reviewed by all authors. At the end, nine articles were included. In conclusion, the assessment of in vivo tailed nuclei in blood smears and accounting for the occurrence of dumbbell-shaped nuclei in the CBMN assay can increase the sensitivity of the CBMN assay for biodosimetry involving a high dose exposure.

Background: The variability of clinical response in radiotherapy (RT) patients revealed that individual radiosensitivity exists in humans. Although several techniques for radiosensitivity assessment are available, fluorescence in situ hybridization (FISH) has proven to be the most reliable cytogenetic technique. This study will review the use of three-color FISH to evaluate the individual radiosensitivity in cancer patients, particularly breast and prostate cancer patients. Also, it will explain factors that should be considered when using this assay in RT patients.Methods: We used the “radiosensitivity”, “fluorescence in situ hybridization”, “FISH”, and “cancer” as medical subject headings. Non-English articles were excluded. Only articles written in English with a full-text PDF format could be found and using three-color FISH for individual radiosensitivity prediction in radiotherapy patients as subjects were included in this review.Results: : In total, 1,905 articles were retrieved from PubMed and PubMed Central databases from 1990 to 2020. The articles were screened, and those that met the inclusion criteria and did not meet the exclusion criteria were reviewed. Finally, we evaluated eight articles in this reviewConclusions: Appropriate assays such as three-color FISH for individual radiosensitivity assessment could optimize the effectiveness of RT treatment and predict the severity of normal tissue toxicity reactions in RT patients.