PTH-94 DRIM expression in colorectal cancer and its possible tumour suppressive role, clinical and prognostic significance

IntroductionDRIM (Down Regulated in Metastasis Protein) is a protein found to be reduced or lost in metastatic cancer cells and has subsequently been found to be identical to Small Subunit Processome Component (UTP20). It is known to be key to ribosomal RNA (rRNA) processing. However, it is primarily present in the nucleus and cell membrane which suggests to link to gene expression and also membrane related cell function. This strongly suggests that it has an important role to play in cancer cell functions. The present study describes our findings on the expression of DRIM in colorectal cancer and its clinical relevance in disease progression and outcome.MethodsThe DRIM/UTP20 protein was assessed on a human colon tissue array by immunohistochemistry. The DRIM/UTP20 gene transcript was quantitatively analysed by real-time quantitative polymerase chain reaction(RT-PCR) in a cohort of fresh frozen colorectal tumours and matched normal mucosal tissues. The median follow-up period of the cohort was 6 years.ResultsColon tissues were stained strongly for DRIM protein and the staining was largely confined to the cytoplasmic and membrane region of the cells. Normal mucosal cells showed stronger staining than colon cancer cells. Patients who had high levels of DRIM had a significant longer overall survival (OS) (138±9.4 months) than those with low levels (70±13.2 months) (p=0.026), with the survival rate respectively for those with high and low levels at 77.2% and 46.6% during the follow-up period. Likewise, patients with high DRIM levels had a highly significant longer disease-free survival (DFS) compared with those with low levels (p