Programmed cell death 4 (Pdcd4) expression in colorectal adenocarcinoma: Association with clinical stage.

The aim of this study was to examine the role of Programmed cell death 4 (Pdcd4) in colorectal adenocarcinoma (CRA). Pdcd4 expression was observed in both the nucleus and cytoplasm in colorectal adenocarcinoma, whereas Pdcd4 was expressed in the nucleus in normal colonic epithelial cells. Loss or weak expression of Pdcd4 was identified in 44 cases (40.7%) of cancer cells. Pdcd4 expression was associated with an increase in the nodal and clinical stage (p=0.022 and p=0.016, respectively). Nuclear staining was identified in 66 cases (61.15%), with no correlation with clinicopathological factors. Conversely, cytoplasmic staining for Pdcd4 was observed in 45 cases (41.7%), and increased according to nodal and clinical stage (p=0.011 and p=0.009, respectively), indicating that aberrant Pdcd4 expression leads to tumor progression. However, Pdcd4 expression was not correlated to disease-free survival time. This study demonstrated that during the tumorigenesis of CRA, loss of nuclear Pdcd4 expression occurs, and during tumor progression, aberrant cytoplasmic expression is present, suggesting a higher clinical stage. Although loss of Pdcd4 was not significantly correlated with survival time, as the prognosis of colorectal cancer varies depending on clinical stage including invasion depth, nodal status and metastatic status, cytoplasmic Pdcd4 expression may be a favorable prognostic marker in CRA.