Immunohistochemical detection of autotaxin (ATX)/lysophospholipase D (lysoPLD) in submucosal invasive colorectal cancer

Purpose: Autotaxin (ATX) is molecularly identical to lysophospholipase D (lysoPLD) and is a main enzyme producing lysophosphatidic acid (LPA), which mediates a broad range of cellular responses including stimulation of cell motility. Patients and Methods: Using immunohistochemical staining, we examined the expression of ATX/lysoPLD in 98 cases of early colorectal cancer with submucosal invasion. ATX/lysoPLD was highly expressed in infiltrating cells in tumor tissue in the submucosal layer, which were characterized as mast cells. Results: The number of ATX/lysoPLD-positive cells was significantly greater in tumors with a macroscopically depressed lesion than in tumors without depression. The density of ATX/lysoPLD-positive cells tended to have a positive correlation with microvessel vascular density (MVD), while it was not correlated with vessel invasion and nodal metastases as well as lymphovascular vessel density (LVD). Conclusion: Our results suggest that local production of LPA through ATX/lysoPLD may weakly correlate with formation of a depressive lesion and tumor angiogenesis in the early stage of colorectal cancer.