Micronucleus Scoring Research Articles

Spontaneously Occurring micronuclei in infiltrating ductal carcinoma of breast: A potential biomarker for aggressive phenotype detection?

Chromosomal instabilities (CIN) manifesting as structural or numerical alterations in the chromosomes are common in malignancies like breast cancer. Assessment of CIN in breast cancer may help to understand its etiopathogenesis. Micronucleus (MN) scoring and aneuploidy have been used to assess the presence of CIN in lymphocytes of various malignancies in the past. In this study, spontaneously occurring MN were counted in epithelial cells on fine needle aspiration cytology (FNAC) smears from 50 patients with benign and malignant breast lesions. Further, the ploidy status and S-phase fraction (SPF) of the samples was determined by flow cytometry. All these were then correlated with grades of breast cancer at cytology. Most IDC cases showed variable number of MN (n = 16, MN mean = 9.3), in contrast to the benign lesions (n = 26) where they were consistently absent. Aneuploidy and SPF analysis also showed a significant difference between benign (n = 10, mean DNA index [DI] = 0.96 ± 0.04, mean SPF= 8.07% ± 2.93) and malignant (n = 10, mean DI = 1.5 ± 0.41, mean SPF = 25.05% ± 10.35) lesions. On statistical analysis, a positive correlation was observed between the grades of IDC and presence of aneuploidy and high SPF (P-values < 0.05); however, the difference between the MN scores of grade 2 and 3 cancers was not significant. The study suggests that MN scoring and aneuploidy may be used to assess the presence of underlying CIN in IDC on FNAC smears. Further, collectively they may be explored for their role as biomarkers for predicting the tumor behavior in the breast cancer patients.

Flow cytometry-based in vitro micronucleus scoring: 384-well plate format provides for higher throughput and low compound requirements

Flow cytometry-based in vitro micronucleus scoring: 384-well plate format provides for higher throughput and low compound requirements

A semi-automated micronucleus-centromere assay to assess low-dose radiation exposure in human lymphocytes

Purpose: The in vitro micronucleus (MN) assay is a reliable method to assess radiation-induced chromosomal damage in human peripheral blood lymphocytes. It is used to evaluate in vivo radiation over-exposure and to assess in vitro chromosomal radiosensitivity. A limitation of the MN assay is the relatively high and variable spontaneous MN frequency that restricts low-dose estimation to doses of about 0.3 gray (Gy). As radiation-induced MN mainly contain acentric fragments and spontaneous MN originate from lagging chromosomes, both MN types can be distinguished from each other by using fluorescence in situ hybridisation (FISH) with a pan-centromeric probe. The aim of this study was to investigate if the sensitivity, reliability and processing time of the MN assay can be enhanced by combining the automated MN assay with pan-centromere scoring.Materials and methods: Blood samples from 10 healthy donors were irradiated in vitro with low doses of gamma-rays. Dose response curves were determined for fully-automated and semi-automated MN scoring and semi-automated scoring of centromere negative MN (MNCM−).Results: A good correlation was obtained between fully-automated and semi-automated MN scoring (r2 = 0.9973) and between fully automated MN scoring and semi-automated scoring of MNCM− (r2 = 0.998). With the Wilcoxon test, a significant p value was obtained between 0 and 0.2 Gy for the fully-automated MN analysis, between 0 and 0.1 Gy for semi-automated MN analysis and between 0 and 0.05 Gy for semi-automated scoring of MNCM−.Conclusion: The semi-automated micronucleus-centromere assay combines high-speed MN analysis with a more accurate assessment in the low-dose range which makes it of special interest for large-scale radiation applications.

CYTOKINESIS-BLOCK MICRONUCLEUS ASSAY IN HUMAN GLIOMA CELLS EXPOSED TO RADIATION

Biological tests are efficient in reflecting the biological influences of several types of generally harmful exposures. The micronucleus assay is widely used in genotoxicity studies or studies on genomic damage in general. We present methodological aspects of cytokinesis-block micronucleus assay performed in human gliomas irradiated in vitro. Eight human glioblastoma cell lines obtained from DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Germany) were gamma-irradiated (60Co) over a dose range of 0-10 Gy. Cytokinesis-block micronucleus assay was performed to quantitate cytogenetic damage. The cells were fixed directly on dishes, stained with fluorochrome DAPI and evaluated under fluorescent and phase contrast microscope. The micronucleus frequency was expressed as a micronuclei (MN) per binucleated cell (BNC) ratio, calculated after scoring at least 100 BNC per dish. The frequency of spontaneous MN ranged from 0.17 to 0.613 (mean: 0.29 ± 0.14). After irradiation increase of MN frequency in the range of 0.312 - 2.241 (mean: 0.98 ± 0.68) was found at 10 Gy. Gliomas are extremely heterogenous in regard to cytogenetic effects of irradiation, as shown in this study by cytokinesis-block micronucleus assay. This test is easily performed on irradiated glioma cell lines and can assist in determining their radiosensitivity. However, in order to obtain reliable and reproducible results, precise criteria for MN scoring must be strictly followed. Simultaneous use of fluorescent and phase contrast equipment improves imaging of morphological details and can further optimize MN scoring.

The role of micronucleus scoring in fine needle aspirates of ductal carcinoma of the breast

Micronucleus (MN) scoring was carried out in benign (fibroadenoma) and malignant (infiltrating ductal carcinoma) breast lesions to evaluate the role of MN as a biomarker in breast carcinomas. We also compared MN scores among different cytological grades of breast carcinoma. A total of 31 archival cases of fibroadenoma (FA) and 40 cases of infiltrating ductal carcinoma (IDC) were selected. The best May-Grünwald-Giemsa (MGG) stained fine needle aspiration cytology (FNAC) smear of each case was selected. The MN scoring was carried out independently by two observers on 1000 epithelial cells in oil immersion magnification (100× objective). The MN scores in FA and IDC were compared. The IDC cases were graded and the MN scores in different cytological grades of IDC were compared. The mean MN scores (± standard deviation) in FA and IDC were 0.6 (± 1.1) and 13.6 (± 12.8), respectively, which were significantly different (P < 0.0001). There were seven grade 1, 13 grade 2, and 20 grade 3 IDCs. The mean MN scores (± standard deviation) of grade 1, 2 and 3 IDC were 4.3 (± 2.3), 11.95 (± 9.2) and 21.1 (± 16.7), respectively. An analysis of variance (anova) test showed a significant difference in MN score between all the grades of IDC (P < 0.05). However, there was no significant difference between fibroadenoma and grade 1 IDC. The Pearson's correlation coefficient showed positive correlations between MN scoring in the different grades of IDC. MN scoring on routinely stained smears of IDCs was significantly higher than in fibroadenoma and was relatively easy, reliable and reproducible. As MN scoring of grade 1 IDC was similar to fibroadenoma, a larger study should be conducted to compare grade 1 IDC with other benign breast lesions.

Salubrious effects of dexrazoxane against teniposide-induced DNA damage and programmed cell death in murine marrow cells

The intention of the present study was to answer the question whether the catalytic topoisomerase-II inhibitor, dexrazoxane, can be used as a modulator of teniposide-induced DNA damage and programmed cell death (apoptosis) in the bone marrow cells in vivo. The alkaline single cell gel electrophoresis, scoring of chromosomal aberrations, micronuclei and mitotic activity were undertaken in the current study as markers of DNA damage. Apoptosis was analysed by the occurrence of a hypodiploid DNA peak and caspase-3 activity. Oxidative stress marker such as intracellular reactive oxygen species production, lipid peroxidation, reduced and oxidised glutathione were assessed in bone marrow as a possible mechanism underlying this amelioration. Dexrazoxane was neither genotoxic nor apoptogenic in mice at the tested dose. Moreover, for the first time, it has been shown that dexrazoxane affords significant protection against teniposide-induced DNA damage and apoptosis in the bone marrow cells in vivo and effectively suppresses the apoptotic signalling triggered by teniposide. Teniposide induced marked biochemical alterations characteristic of oxidative stress including accumulation of intracellular reactive oxygen species, enhanced lipid peroxidation, accumulation of oxidised glutathione and reduction in the reduced glutathione level. Prior administration of dexrazoxane ahead of teniposide challenge ameliorated these biochemical alterations. It is thus concluded that pretreatment with dexrazoxane attenuates teniposide-induced oxidative stress and subsequent DNA damage and apoptosis in bone marrow cells. Based on our data presented, strategies can be developed to decrease the teniposide-induced DNA damage in normal cells using dexrazoxane. Therefore, dexrazoxane can be a good candidate to decrease the deleterious effects of teniposide in the bone marrow cells of cancer patients treated with teniposide.

Micronucleus in atypical squamous cell of undetermined significance

The aim of this study was to explore the role of micronucleus (MN) scoring in distinguishing the smears of atypical squamous cell of undetermined significance (ASCUS) with reactive outcome versus ASCUS with cervical intraepithelial lesions (CIN) outcome. In this retrospective study, there were 53 cases of ASCUS diagnosed on cervical cytology smear and of which 30 cases showed reactive changes (group 1) and 23 cases showed CIN (group 2) on follow up histology. MN score of group 1 was compared with group 2 in conventional Papanicolaou's stained smear. The micronucleated cell per 1,000 epithelial cells in oil immersion magnification (100× objective) was counted by two observers and expressed as MN score. The data were compared in the two groups. The mean MN score was 2.8667 ± 2.20866 in group 1 and 8.3478 ± 6.44987 in group 2 cases. The Student's t-test showed significant difference of MN score in group 2 compared to group 1 (P < 0.0001). MN score may be helpful in identifying the true CIN cases that are mislabeled as ASCUS on cervical smear. In future, MN score can be used as an additional biomarker in cervical cancer screening.

A Verification of Treatment Protocol in Fractionated Radiotherapy by Biological Dosimetry

In radiation therapy of cancer, any possible mistakes that may occur in prescribed tumour dose calculation and/ or in treatment set up could also be checked by the biological dosimetry. In order to verify this, 20 patients having pelvic area tumours with no prescribed chemotherapy were selected. Their peripheral blood samples were collected before starting fractionated radiotherapy and at some definite time during treatment. Equivalent whole body doses (EWBD) were calculated from patient’s weights, irradiated volumes and total tumor doses given until the date of blood sample collection during treatment. Each patient’s EWBD was given in vitro to blood samples that were collected before starting radiotherapy. Radiation induced chromosome damage in lymphocytes were measured by micronucleus (MN) induction. The relationship between the micronucleus frequencies (MN/BN) scored during therapy ( in vivo ) and the micronucleus frequencies scored after the application of in vitro EWBD was investigated. MN/BN rates scored following in vitro application of EWBD differed between 0.195 and 0.540, whereas MN/BN rates obtained during radiotherapy equivalent to EWBD differed between 0.213 and 0.625. It was shown that there was no significant difference (p=0.653) between the MN scores following in vitro applied EWBD and MN scores obtained in vivo . The existence of this correlation has confirmed the correct application of fractionated radiotherapy and treatment setup for the patients.

Micronucleus assay in buccal smears of breast carcinoma patients

The aim of this study is to compare micronucleus assay in buccal smear of breast carcinoma patients versus normal benign cases as control group. In this prospective study, we selected a total 32 patients of carcinoma of breast and 49 patients of benign breast lesions diagnosed in fine needle aspiration cytology (FNAC). Acridine orange stain was done on buccal smears of these cases and micronucleus (MN) scoring was performed in 40× 0bjective in a fluorescent microscope. The MN score was expressed as positivity per 1,000 cells. The MN scoring in buccal smear was compared in malignant and benign breast cases. In fluorescence microscope, the micronucleus was detected as round orange shaped small intracytoplasmic structure around the nucleus. The mean MN scores in buccal smears of benign and carcinoma cases were 0.5014 ± 0.45768 and 2.1938 ± 1.08656 cases respectively. Independent sample Student's t test showed significantly high MN score in buccal smear of the cancer patients (P < 0.001). Micronucleated cells are significantly increased in buccal cells of the breast carcinoma cases. The increased number of MN in buccal smears raises the possibility that the genetic damage in breast cancer patients is generalized. In future, MN scoring could be used as biomonitoring of DNA damage and in early detection of high risk cases of carcinoma of breast.

Micronucleus and its applications

Micronucleus (MN) is a small additional nucleus and is readily identifiable by light microscopy. Biologically, micronuclei are the chromosome fragments or whole chromosomes that lag behind at anaphase during nuclear division. MN occurs due to genetic damage of the cell and the MN scoring is the indicator of the genetic damage. Therefore MN scoring can be used in various clinical setting such as to supervise genotoxicity, biomonitoring of diseases, screening of preneoplastic diseases and identification of high risk patients. In this brief review, the morphology, etiology, estimation, and applications of MN have been discussed.

Heritability of baseline and induced micronucleus frequencies

The scoring of micronuclei (MN) is widely used in biomonitoring and mutagenicity testing as a surrogate marker of chromosomal damage inflicted by clastogenic agents or by aneugens. Individual differences in the response to a mutagenic challenge are known from studies on cancer patients and carriers of mutations in DNA repair genes. However, it has not been studied to which extent genetic factors contribute to the observed variability of individual MN frequencies. Our aim was to quantify this heritable genetic component of both baseline and radiation-induced MN frequencies. We performed a twin study comprising 39 monozygotic (MZ) and 10 dizygotic (DZ) twin pairs. Due to the small number of DZ pairs, we had to recruit controls from which 38 age- and gender-matched random control pairs (CPs) were generated. For heritability estimates, we used biometrical modelling of additive genetic, common environmental, and unique environmental components (ACE model) of variance and direct comparison of variance between the sample groups. While heritability estimates from MZ to DZ comparisons produced inconclusive results, both estimation methods revealed a high degree of heritability (h(2)) for baseline MN frequency (h(2) = 0.68 and h(2) = 0.72) as well as for the induced frequency (h(2) = 0.68 and h(2) = 0.57) when MZ were compared to CP. The result was supported by the different intraclass correlation coefficients of MZ, DZ and CP for baseline (r = 0.63, r = 0.31 and r = 0.0, respectively) as well as for induced MN frequencies (r = 0.79, r = 0.74 and r = 0.0, respectively). This study clearly demonstrates that MN frequencies are determined by genetic factors to a major part. The strong reflection of the genetic background supports the idea that MN frequencies represent an intermediate phenotype between molecular DNA repair mechanisms and the cancer phenotype and affirms the approaches that are made to utilise them as predictors of, for example, cancer risk.

Automated scoring of lymphocyte micronuclei by the MetaSystems Metafer image cytometry system and its application in studies of human mutagen sensitivity and biodosimetry of genotoxin exposure

Automated image analysis scoring of micronuclei (MN) in cells can facilitate the objective and rapid measurement of genetic damage in mammalian and human cells. This approach was repeatedly developed and tested over the past two decades but none of the systems were sufficiently robust for routine analysis of MN until recently. New methodological, hardware and software developments have now allowed more advanced systems to become available. This mini-review presents the current stage of development and validation of the Metasystems Metafer MNScore system for automated image analysis scoring of MN in cytokinesis-blocked binucleated lymphocytes, which is the best-established method for studying MN formation in humans. The results and experience of users of this system from 2004 until today are reviewed in this paper. Significant achievements in the application of this method in research related to mutagen sensitivity phenotype in cancer risk, radiation biodosimetry and biomonitoring studies of air pollution (enriched by new data) are described. Advantages as well as limitations of automated image analysis in comparison with traditional visual analysis are discussed. The current increased use of the Metasystems Metafer MNScore system in various studies and the growing number of publications based on automated image analysis scoring of MN is promising for the ongoing and future application of this approach.

Potential thresholds for genotoxic effects by micronucleus scoring

The concept of thresholds in genotoxicity has been open for debate in the last decades. The micronucleus (MN) test contributed to a large extent in understanding the dose-response relationship for aneugens and clastogens. The threshold concept for aneuploidy is well accepted by the scientific community based on the data and for mechanistic reasons. The concept of threshold for clastogens is still challenging. Acceptance is based on a case-by-case basis together with thorough mechanistic understanding of the different steps from the mutagen-target interactions to MN formation for this class of genotoxicants. This review summarises the significant achievements in the assessment of threshold for genotoxins using the MN test and concludes with an overview of knowledge gaps and recommendations.

Laser scanning cytometry for automation of the micronucleus assay

Laser scanning cytometry (LSC) provides a novel approach for automated scoring of micronuclei (MN) in different types of mammalian cells, serving as a biomarker of genotoxicity and mutagenicity. In this review, we discuss the advances to date in measuring MN in cell lines, buccal cells and erythrocytes, describe the advantages and outline potential challenges of this distinctive approach of analysis of nuclear anomalies. The use of multiple laser wavelengths in LSC and the high dynamic range of fluorescence and absorption detection allow simultaneous measurement of multiple cellular and nuclear features such as cytoplasmic area, nuclear area, DNA content and density of nuclei and MN, protein content and density of cytoplasm as well as other features using molecular probes. This high-content analysis approach allows the cells of interest to be identified (e.g. binucleated cells in cytokinesis-blocked cultures) and MN scored specifically in them. MN assays in cell lines (e.g. the CHO cell MN assay) using LSC are increasingly used in routine toxicology screening. More high-content MN assays and the expansion of MN analysis by LSC to other models (i.e. exfoliated cells, dermal cell models, etc.) hold great promise for robust and exciting developments in MN assay automation as a high-content high-throughput analysis procedure.

Automated image analysis of micronuclei by IMSTAR for biomonitoring

For many years, the analysis of micronuclei (MN) has been successfully applied to human biomonitoring of in vivo genotoxin exposure and provides a sensitive and relatively easy methodology to assess genomic instability. However, there is a need for automation of MN analysis for rapid, more reliable and non-subjective MN detection. In this review, we evaluate the application of automated image analysis of the in vitro cytokinesis-block MN assay on human lymphocytes for human biomonitoring, starting with the requirements that should be fulfilled by a valid and efficient image analysis system. Considering these prerequisites, we compare the automated facility developed in the framework of the European Union-project NewGeneris with other already published systems for automated scoring of MN. Although the automated scoring of MN is now put into place, extension to other cytome assay end points such as apoptosis, necrosis, nuclear buds and nucleoplasmic bridges would greatly enhance the specificity and sensitivity of future biomonitoring studies. Inclusion of these end points would also allow an automated approach to in vitro genotoxicity testing. In addition, automated scoring of the MN assay in exfoliated buccal cells would be very beneficial for large-scale biomonitoring studies, as cells can be collected in a minimally invasive manner.

Flow cytometric scoring of micronucleated erythrocytes: an efficient platform for assessing in vivo cytogenetic damage

The relative simplicity of the micronucleated erythrocyte endpoint has made it amenable to automated scoring approaches. Flow cytometry is one such scoring platform that has been employed successfully. This review describes the evolution and properties of flow cytometry-based scoring of micronucleated erythrocytes. The methodology has become widely applied to rodent blood specimens and the high throughput nature of the technology provides a number of advantages over manual microscopic scoring. For instance, the ability to efficiently survey many dose levels and many more cells per specimen relative to microscopy benefits studies that are designed to identify no observable effect levels or lowest observable effect levels. Furthermore, flow cytometry makes it practical to study species with low spontaneous reticulocyte (RET) counts and micronucleus (MN) frequencies, thereby facilitating integration of blood-based micronucleated reticulocyte (MN-RET) frequency measurements into experiments conducted across species of toxicological interest. This capability enhances genotoxicity assessments that have historically been made in dedicated MN tests performed in one species. Importantly, the feasibility of using MN-RET frequencies in blood from humans as an index of genetic damage in bone marrow opens a critical area of application that had not been practical previously. We conclude with recommendations for additional work that is needed to more fully realise the potential of flow cytometric in vivo MN scoring.

Micronucleus in Cervical Intraepithelial Lesions and Carcinoma

Aims and Objectives: To score and compare micronucleus (MN) in the whole spectrum of cervical lesions including normal, inflammatory, abnormal squamous cell of undetermined significance (ASC-US), low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL) and invasive cancer (IC) and to evaluate the role of MN as a biomarker in different pre-neoplastic and neoplastic lesions. Materials and Methods: A total of 224 slides, comprised of normal (40), inflammatory (40), ASC-US (30), LSIL (38), HSIL (30) and IC (46), were studied. All the cases of HSIL, IC and ASC-US had histopathology. The LSIL, normal and inflammatory smears were again reviewed by 2 experienced cytopathologists independently. Two observers separately and independently counted the number of micronucleated cells per 1,000 of epithelial cells in oil immersion magnification (×100 objective) which was expressed as MN score per 1,000 cells. Results: The mean MN scores ± SD in normal, inflammatory, ASC-US, LSIL, HSIL and IC cases of cervical lesions were 1.02 ± 1.59, 0.4250 ± 0.71208, 2.87 ± 2.21, 4.7368 ± 5.62179, 21.30 ± 17.18 and 18.50 ± 9.54, respectively. MN scores of IC and HSIL were significantly high compared to the normal (p < 0.000), the inflammatory (p < 0.000), the ASC-US (p < 0.000) and to the LSIL (p < 0.000) group (analysis of variance test). LSIL showed significant difference with the normal (p = 0.043), the inflammatory (p = 0.019), the HSIL (p < 0.000) and the IC (p < 0.000) group but not with the ASC-US (p = 0.342) group. Conclusions: MN scoring on the epithelial cells of cervix could be used as a biomarker in cancer screening. This is an easy, simple, reliable, reproducible and objective test which can be performed on routinely stained smears.

Current status of biodosimetry based on standard cytogenetic methods

Knowledge about dose levels in radiation protection is an important step for risk assessment. However, in most cases of real or suspected accidental exposures to ionizing radiation (IR), physical dosimetry cannot be performed for retrospective estimates. In such situations, biological dosimetry has been proposed as an alternative for investigation. Briefly, biodosimetry can be defined as individual dose evaluation based on biological endpoints induced by IR (so-called biomarkers). The relationship between biological endpoints and absorbed dose is not always straightforward: nausea, vomiting and diarrhoea, for example, are the most well-known biological effects of individual irradiation, but a precise correlation between those symptoms and absorbed dose is hardly achieved. The scoring of unstable chromosomal-type aberrations (such as dicentrics and rings) and micronuclei in mitogen-stimulated peripheral blood, up till today, has been the most extensively biodosimetry assay employed for such purposes. Dicentric assay is the gold standard in biodosimetry, since its presence is generally considered to be specific to radiation exposure; scoring of micronuclei (a kind of by-product of chromosomal damages) is easier and faster than that of dicentrics for dose assessment. In this context, the aim of this work is to present an overview on biodosimetry based on standard cytogenetic methods, highlighting its advantages and limitations as tool in monitoring of radiation workers' doses or investigation into accidental exposures. Recent advances and perspectives are also briefly presented.

The impact of quercetin on cisplatin-induced clastogenesis and apoptosis in murine marrow cells

The aim of the present investigation is to determine whether the quercetin in combination with cisplatin can ameliorate cisplatin-induced clastogenesis and apoptosis in the bone marrow cells of mice. The scoring of chromosomal aberrations, micronuclei and mitotic activity were undertaken in the current study as markers of clastogenicity. Apoptosis was analysed by the Annexin V-propidium iodide assay and the occurrence of a hypodiploid DNA peak. Oxidative stress markers such as bone marrow lipid peroxidation and reduced glutathione were assessed as a possible mechanism underlying this amelioration. Quercetin was neither clastogenic nor apoptogenic in mice at doses equivalent to 50 or 100 mg/kg for 2 days. Pre-treatment of mice with quercetin significantly reduced cisplatin-induced clastogenesis and apoptosis in the bone marrow cells and these effects were dose and time dependent. Prior administration of quercetin ahead of cisplatin challenge ameliorated oxidative stress markers. Overall, this study provides for the first time that quercetin has a protective role in the abatement of cisplatin-induced clastogenesis and apoptosis in the bone marrow cells of mice that resides, at least in part, in its antioxidant effects. Therefore, quercetin can be a good candidate to decrease the deleterious effects of cisplatin in the bone marrow cells of cancer patients treated with this drug.

Micronucleus in atypical urothelial cells

The objective of this study is to evaluate the role of micronuclei (MN) in identifying the atypical urothelial cells urinary cytology. This is a retrospective study of a total of 30 cases of urine samples. Of these, 15 cases were selected where the initial diagnosis was atypical urothelial cell and later turned out as malignant cells on follow-up histopathology. The rest of the 15 cases were reported as normal urothelial cells. The number of MN in 1,000 urothelial cells was counted in all the cases and was expressed as percentage. All the cases diagnosed as atypical urothelial cells show the presence of MN. The mean number of MN was 2.53 ± 0.99%. No MN was noted in any of the normal urothelial cells in control cases. The Student's t-test of MN scoring was highly significant (P < 0.000) in test (atypical urothelial cells) versus control group (benign urothelial cells). MN is an important biomarker of malignancy. Micronuclear score in atypical urothelial cells in urine cytology smears may help in proper diagnosis of the case.