Identification of low abundance proteins in colorectal cancer tissues.

Background: Detection of low abundance proteins always possesses challenges even with the currently available proteomics technologies.

Objective: We aimed to evaluate the low abundance differentially expressed proteins in colorectal cancerous tissues as compared to colorectal normal tissues.

Methodology: Protein separation was carried out by using the coupling methods of hydroxyapatite chromatography and SDS-PAGE followed by mass spectrometry analysis.

Results: Five of the membrane associated low abundance proteins, namely uncharacterized protein C5orf4, coiled-coil domain containing protein 152, DnaJ homolog subfamily C member 22, tumor suppressor candidate 3 and leucine-rich repeat transmembrane neuronal protein 4 that previously only reported at the genome level were identified.

Conclusions: The proteins were isolated from the cancerous tissues as either up-regulated or down-regulated proteins as compared to normal tissues and therefore may play important roles in cancer development.