Table 1

Quantititative immunohistochemistry (IHC) in colorectal cancer (CRC): previous reports

Study	Specimen	Antigen	Quantification method	Image-acquisition technique	Outcome
Matkowskyj et al23	Stable CRC cell lines expressing gastrin-releasing peptide at between 10² and 10⁶ receptors per cell	Gastrin-releasing peptide	Selection of region of interest, chromogen present per pixel	RGB	Chromogen quantity as determined by quantitative IHC tightly linearly correlated with gastrin-releasing peptide receptor number
Bhargava et al20	CRC tissue microarray	Epidermal growth factor receptor	Maximal intensity of microarray tissue core	RGB	Semiquantitative manual scoring correlated well with image analysis
Messersmith et al24	CRC and normal colon tissue microarrays	Epidermal growth factor receptor	Mean intensity of 3× regions of interest	RGB	Image analysis highly reproducible, and correlated well with western blotting, ELISA and manual scoring
Peretti et al25	CRC and normal colon	Heparanase-2 and syndecan-1	Percentage labelled cells and staining intensity	RGB	Expression of heparanase-2 and syndecan-1 was related to neoplasia. Cut-off points for staining intensity were proposed which gave very high sensitivities and specificities for the identification of CRC.