Id-1: Regulator of EGFR and VEGF and potential target for colorectal cancer therapy

Background: The helix-loop-helix transcription factor Id-1 (an inhibitor of differentiation and DNA binding) plays a role in development and progression of many tumours. Id-1 is known to exert its effects on the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor (VEGF). The aim of this study was to reveal whether there was a relationship between Id-1 and EGFR and VEGF in colorectal carcinoma. Methods: Tumour and non-tumour tissue specimens from 46 cases of colorectal carcinoma were exposed to immunohistochemical staining for Id-1, EGFR and VEGF. The relationship between the degree of staining and tumour grade, tumour stage and all tumour markers was investigated. Results: Tumour cells showed positive staining for Id-1 in 43 cases (93.5%), for EGFR in 41 cases (89%) and for VEGF in 42 cases (91%). There was a significant relation between the tumour grade and the degree of staining for Id-1, EGFR and VEGF. The relation between the tumour stage and the degree of staining for Id-1, EGFR and VEGF was also significant. There was a significant relation between Id-1 expression and EGFR and VEGF expressions. Non-tumoural tissue specimens were not stained with Id-1 and EGFR antibodies in any of the cases, but stained with VEGF antibody in 3 cases. Conclusion: This study revealed that Id-1, EGFR and VEGF took part in development and progression of colorectal carcinomas and that Id-1 was associated with regulations of EGFR and VEGF. The results of this study support the idea that not only EGFR and VEGF but also Id-1 could be new targets in cancer treatment.