Evaluation of Microvascular Density as a Predictive Indicator for Malignant Transformation of Oral Epithelial Dysplasia (OED)
A wealth of translational and clinical research supports the key role of angiogenesis during malignant transformation. Past human studies involving pre-neoplastic lesions of breast and cervical tissue have revealed a positive correlation between angiogenesis and the progression, prognosis and metastasis of ductal carcinoma in situ and cervical intraepithelial neoplasia. In addition to studies involving human breast and cervical tissue, numerous studies have been carried out to examine the association of between angiogenesis and progression of OED. Siar et al., utilizing IHC staining with CD31 and CD34 antigens, demonstrated higher MVD scores in OED and bronchial tissue as compared to benign tissue, and an increasing MVD score as the histologic grade of the lesion increased (1). These data present compelling evidence regarding MVD’s importance in carcinogenesis. To our knowledge, however, no one has conducted a longitudinal assessment to determine whether or not increased microvascular density positively correlates with malignant transformation.
The objective of this study is to determine whether MVD (as determined by CD31 expression) in oral premalignant lesions is associated with high-risk epithelial dysplasia, and whether increases in MVD can serve as a molecular biomarker for identifying a subgroup of patients that are at increased risk of malignant transformation of their premalignant lesions.
This case-controlled retrospective study identified a cohort of age and lesional-site matched patients whose lesions either remained premalignant over >4 years or transformed to OSCC over the same time period (n=5 for both OSCC and control, 29 and 32 biopsies analyzed, respectively).
Platelet endothelial cell adhesion molecule (PECAM-1/CD31), which is a member of the immunoglobin super family of cell adhesion molecules, is a primary constituent of endothelial cell-cell junctions in confluent vascular beds (2). In addition, CD31 has been identified as one the most specific immunohistochemical markers to detect endothelial cells lining vascular channels.
Immunohistochemical staining for CD31 was performed on deparaffinized 4mm thick sections from each biopsy tissue block. CD31 (PECAM-1) mouse monoclonal antibody was utilized to detect endogenous levels of total CD31 protein with incorporation of appropriate positive and negative control tissues. Microvascular density analyses are near completion. Slides were converted to digital slide images using the ScanScope XT by Aperio (Vista, California). Scan output is in the form of svs files, which are then viewed, annotated and stored via Aperio’s Imagescope viewer software. Tissue Studio 3.5 software (Definiens, Munich, Germany) is used for image analyses. This system uses a context-based, relational analysis of the component pixels in digital slide images. This state-of-the-art imaging system provides a wealth of experimental data in a rapid and consistent fashion and eliminates concerns that arise via traditional reviewer-based methods of slide images. Preliminary data analyses are ongoing (intrapatient comparisons- Repeated Measures ANOVA, followed by the Bonferoni multiple comparisons test, interpatient comparisons-ANOVA with a Tukey’s post hoc test, potential for MVD-OED association with progression-Pearson’s product moment correlation coefficient) and will be completed by June 2013.
1. Siar CH et al. Angiogenic squamous dysplasia-like phenomenon in oral epithelial precursor lesions. Eur J Med Res 2009.
2. Albelda S et al. Molecular and cellular properties of PECAM-1 (endoCAM/CD31): A novel vascular cell-cell adhesion Molecule. The Journal of Cell Biology, Volume 114, Number 5, September 1991.