Micronucleus in cervical intraepithelial lesions and carcinoma

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.

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.

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.

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.