PECAM1 and colorectal carcinoma: Furthermore, Harris et al, showed that the assessment of both small‐ and large‐vessel involvement in colorectal carcinoma could not be improved by application of D2‐40 and CD31.40 We acknowledge, however, that the use of IHC can be useful in selected difficult cases (e.g. cases with extensive retraction artefact), and when used in the correct context will probably further improve interobserver agreement.