Specific changes of chromatin structure in nuclei of normal epithelium adjacent to laryngeal squamous cell carcinoma. A preliminary study of 82 cases

Potentially malignant lesions of the upper aerodigestive tract

Mucosal lesions of the upper aerodigestive tract usually concern the squamous epithelium of the surface. Many precancerous alterations now designated as potentially malignant are caused by DNA damage resulting from long term exposure to tobacco and alcohol consumption. The distinction from conditions with a similar phenotype but caused by different reasons such as viral infection may be difficult. Furthermore, a magnitude of similar appearing lesions with different clinical background and different biological behavior are discussed in this paper.

Human papillomavirus-related cellular changes measured by cytometric analysis of DNA ploidy and chromatin texture

BACKGROUND

Image cytometry has provided two highly sensitive markers for the identification of the malignant potential of squamous lesions. Aneuploidy and chromatin texture have been investigated as quantitative measures of nuclear damage in premalignant lesions and carcinoma. Real-time PCR methods have evolved to yield highly specific measurements of mRNA expression in very sparse cellular samples.

METHODS

Human papillomavirus (HPV) 16 and 18 E7 mRNA expression was measured using quantitative RT-PCR. DNA index and chromatin measures were taken from image cytology samples. The chromatin features, through discriminant analysis, were aggregated into a score, and both measurements were related to mRNA expression.

RESULTS

mRNA level and DNA index show an increasing trend over increasing histological grades. However, DNA index and chromatin score were not correlated to mRNA levels in these samples. Chromatin score differed by mRNA type found with HPV 18 infected samples having a higher score than those with HPV 16. Samples infected with HPV 16 and HPV 18 had even higher chromatin scores.

CONCLUSIONS

DNA index and chromatin score were not directly correlated with mRNA levels. However both mRNA and DNA index were related to histological grade, and chromatin score was associated with HPV type. Therefore, DNA index and mRNA levels could be independent predictors of cervical dysplasia, and chromatin score could be related to the viral integration process in cells infected with HPV 18 or dual infections.