Microsatellite instability: impact on cancer progression in proximal and distal colorectal cancers

Whilst individual planning of treatment and follow-up in every colorectal cancer case is an increasing demand, prognostic markers are needed for predicting cancer progression in the primary phase. We studied the effect of replication error (RER)-positivity on colorectal cancer progression by analysing 255 colorectal cancer specimens by polymerase chain reaction (PCR) and fragment analysis and correlating the results with the clinical and histological features of the tumour and with patient outcome. RER-positivity was detected in 12% (28/235) of cases. It was associated with proximal location of the tumour (P