Double-Stranded B-DNA: Presence in Human Melanoma Tissue (Stage III)

Abstract

Stage III melanoma refers to tissue tumors that have spread to regional lymph nodes, or have developed in transit metastasis (regional). With treatment this pathology is considered intermediate to high risk for recurrence locally or for distant metastasis. Consequently, new approaches towards treating melanoma need to be developed. Right-handed double-stranded (ds-) B-DNA is the most common structure that makes up the majority of DNA. Tissue samples were preserved in several different tissue fixatives (molecular grade), in order to better characterize DNA and DNA-protein complex interactions (10% formalin, 10% neutral buffered formalin, Clarke's solution, Carnoy's, solution, and zinc formalin fixative). Previously, we have characterized the epidermis of human skin for the presence of ds-B-DNA as it undergoes cell death [i.e., apoptosis and terminal differentiation]. Our data reveals the distribution and intensity of anti-B-DNA, anti-single-stranded DNA, anti-Z-RNA antibody binding, and a variety of different anti-melanoma antibody, in human melanoma (IIIA, IIIB, and IIIC). We carefully observed the differences in DNA structure within the papillary dermis. The intensity of immunohistochemical staining is different within certain regions of the cancerous growth, namely, less immunohistochemical staining in the lateral regional and much more in the vertical areas. Less ss-DNA was seen in the vertical areas (reticular dermis). Employing novel histotechnological processing procedures we were able to better preserve the tissue-bound ds-B-DNA as intact, unaltered and non-denatured molecules (1). This has resulted in improvements involving laser capture dissection techniques for the isolation of genetic materials. 1. Gagna CE, et al., (2007) Novel DNA Staining Method and Processing Technique for the Quantification of Undamaged Double-Stranded DNA in Epidermal Tissue Sections by PicoGreen Probe Staining and Microspectrophotometry. Journal of Histochemistry and Cytochemistry. 55: 999-1014. This research project was supported in part by a 2011 ISRC grant.