Thus, based on the observed existence of aberrant cases in the immunonegative p53 group and the fact that deletion is the most frequent event in tumors, whether accompanied by the mutation of the other allele or not, we hypothesized that TP53 deletion/mutation analysis could be a valid method to estimate TP53 status and to assign tumors/patients to the CIN subtype. This evidence concerns the gene TP53 and cervical squamous intraepithelial neoplasia.