Tear film levels of interleukin- (IL-) 6, IL-8, and vascular endothelial growth factor (VEGF) were investigated over time, and preoperative concentrations were linked to corneal neovascularization and pterygium size.
The use of single intra lesional injection of Avastin in pterygium decreased vascularity and decreased VEGF expression in injected pterygium after one month.
The high expression levels of tumor protein p53 (TP53) observed in laboratory studies of pterygium seem to contradict the fast-growing nature of its clinical behavior, and TP53 mutations have been suggested.
Our study demonstrated that inactivation of p53 in pterygium may influence miR-200a, resulting in ZEB1/ZEB2 up-regulation and EMT processing of pterygium.
We studied, with immunohistochemistry, the presence and localization of thymine dimers in the epithelial and stromal components of the human primary pterygium and its recurrences with a special emphasis on the vascular network and its interactions with the p53 tumor suppressor gene protein.
These studies indicate that tumor suppressor gene p53 and other genes associated with DNA repair, cell proliferation, migration and angiogenesis are critical for the development of pterygium.
Antibodies raised against VEGF and p53 were used to analyze the distribution and expression of these markers in pterygium and normal human conjunctiva were used as negative control.
Molecular genetic alterations reported in association with pterygium include loss of heterozygosity (LOH), point mutations of proto-oncogenes, such as K-ras and alterations in the expression of tumor suppressor genes, such as p53 or p63.
HPV 16/18 E6 contributes to HPV-mediated pterygium pathogenesis as it is partly involved in p53 inactivation and is expressed in HPV DNA-positive pterygium.
Other findings in pterygium include the frequent detection of HPV DNA, ocular surface changes such as the overexpression of various proteins, including defensins and phospolipases D, as well as the up-regulation of growth factors, such as bFGF or VEGF.
There were no significant differences between pterygium and control groups in age, sex, and distribution of genotype and allelic frequency of VEGF-460 polymorphism.
Several researchers believe that pterygium is UV-related and that abnormal expression of p53 protein and infection with human papillomavirus (HPV) are risk factors for pterygium, but their experiments have been inconclusive.