Colorectal polypoid lesions and expression of vascular endothelial growth factor in a consecutive series of endoscopic and surgical patients

Can Vascular Endothelial Growth Factors and CD34 Expression Implement NICE (Narrow-Band Imaging International Colorectal Endoscopic) Classification in Colorectal Polypoid Lesion Diagnosis?

BACKGROUND

Vascular endothelial growth factor (VEGF) is a subfamily of growth factors involved in angiogenesis; CD34+ cells are normally found in endothelial progenitor cells and endothelial cells of blood vessels. Colonic adenomatous polyps may not always be completely removable endoscopically, and a preoperative diagnosis might still be necessary. The aim of the study was to evaluate whether VEGF-A, VEGF-C and CD34 mRNA expression along colorectal carcinogenesis steps can implement NICE (Narrow-Band Imaging International Colorectal Endoscopic) classification in the diagnosis of malignancy in colorectal polypoid lesions.

METHODS

Seventy-one subjects with colonic adenoma or cancer who underwent screening narrow-band imaging (NBI) colonoscopy were prospectively enrolled in the MICCE1 project (Treviso center). Polyps were classified according to the NICE classification. Real-time RT-PCR for VEGF-A, VEGF-C and CD34 mRNA expression was performed. Nonparametric statistics, receiver-operating characteristic curve analysis and logistic multiple regression analysis were used.

RESULTS

VEGF-A and CD34 mRNA expression was significantly higher in sessile adenomas than in polypoid ones (p < 0.001 and p = 0.01, respectively). VEGF-A, VEGF-C and CD34 mRNA expression was significantly higher in adenocarcinoma than in adenoma (p = 0.01, p = 0.01 and p = 0.01, respectively). The accuracy of VEGF-A, VEGF-C and CD34 mRNA expression for prediction of malignancy was 0.79 (95% CI 0.65-0.90), 0.81 (95% CI 0.66-0.91) and 0.80 (95% CI 0.65-0.90), respectively, while the accuracy of the NICE classification was 0.85 (95% CI 0.72-0.94). The determination coefficient R2, which indicates the amount of the variability explained by a regression model, for NICE classification alone was 0.24 (p < 0.001). A regression model that included NICE classification and VEGF-C mRNA expression showed an R2 = 0.39 as well as a model including NICE classification and CD34 mRNA levels.

CONCLUSIONS

This study demonstrated that VEGF-C and CD34 mRNA levels might be useful to stratify colorectal polyps in different risk of progression classes by implementing the accuracy of the NICE classification. Studies on in vivo detection of these markers are warranted.

Interferon-Gamma and Tumor Necrosis Factor-Related Weak Inducer of Apoptosis Expression in Neoangiogenesis in Colorectal Polypoid Lesions

BACKGROUND

Interferon gamma (IFNγ) and tumor necrosis factor-related weak inducer of apoptosis (TWEAK) molecules seem to have a potential effect on angiogenic factors such as vascular endothelial growth factor (VEGF). The aim of this study was to assess a possible interplay between IFNγ and TWEAK cytokines and VEGF machinery in the different steps of colorectal carcinogenesis.

METHODS

A total of 92 subjects with colonic adenoma or cancer who underwent screening colonoscopy or surgery were prospectively enrolled. Polypoid lesion tissue samples were collected and frozen. Real-time reverse transcription polymerase chain reaction for IFNγ, TWEAK, and VEGF-A mRNA expression was performed. Immunoassays for VEGF-A, VEGF-C, VEGFR-1, VEGFR-2, and VEGFR-3 were also performed. Nonparametric statistics, receiver operating characteristic curve analysis, and logistic multiple regression analysis were used.

RESULTS

IFNγ and TWEAK mRNA expression was higher in patients with T2 or more advanced colorectal cancer than in those with adenomas or T1 cancer (p < 0.001 and p = 0.01, respectively). IFNγ and TWEAK mRNA expression levels directly correlated with VEGF-A mRNA expression levels (rho = 0.44, p < 0.001 and rho = 0.29, p = 0.004, respectively). On the contrary, IFNγ and TWEAK mRNA expression levels inversely correlated with VEGF-C protein levels (rho = -0.29, p = 0.04 and rho = -0.31, p = 0.03, respectively). Similarly, IFNγ and TWEAK mRNA expression levels inversely correlated with VEGFR2 protein levels (rho = -0.38, p = 0.033 and rho = -0.40, p = 0.025, respectively).

CONCLUSION

This study showed that in colorectal polypoid lesions, IFNγ and TWEAK expressions are directly correlated to VEGF-A expression but inversely correlated with VEGFR2 levels, suggesting a possible feedback mechanism in the regulation of VEGF-A expression.