ID1 and neoplasm: To assess the association between the presence of HPV types 16, 18, 31, 33 and 35 with tumour aggressiveness and Id-1 expression in breast cancer in Syrian women, we examined the expression of the E6 onco-protein of high-risk HPVs along with Id-1 expression in all our breast tissue samples by immunohistochemistry using tissue microarray methodology.