Genomic instability is an important biomarker in the progression of cervical carcinoma. DBD-FISH (DNA breakage detection-fluorescence in situ hybridization) is a sensitive method that detects strand breaks, alkali-labile sites, and incomplete DNA excision repair in cells of the cervical epithelium. This technique integrates the microgel immersion of cells from a vaginal lesion scraping and the DNA unwinding treatment with the capacity of FISH integrated into digital image analysis. Cells captured within an agarose matrix are lysed and submerged in an alkaline unwinding solution that generates single-stranded DNA motifs at the ends of internal DNA strand breaks. After neutralization, the microgel is dehydrated and the cells are incubated with DNA-labeled probes. The quantity of a hybridized probe at a target sequence corresponds to the measure of the single-stranded DNA produced during the unwinding step, which is equivalent to the degree of local DNA breakage. DNA damage does not show uniformly throughout the entire DNA of a cell; rather, it is confined to specific chromosomal sites. In this chapter, an overview of the technique is supplied, focusing on its ability for assessing the association between DNA damage in specific sequences and in the progressive stages of cervical carcinoma.

The chromatin dispersion test (CDT) is based on the removal of nuclear proteins under the assumption that cells with fragmented DNA produce a typical halo of circular DNA loops, which is absent in cells with non-fragmented DNA. This method represents a simple, rapid, accurate, highly reproducible, and inexpensive technique to assess nuclear DNA damage in somatic cells. The visualization of DNA damage and the capacity of the test to provide a threshold value to discriminate between high and low levels of cervical lesions would aid in determining the malignant transformation. All of these advantages associated with the CDT protocol could promote this technique as a tool for the quick and reliable diagnosis of cervical epithelial disorders, even at primary-care centers.