Hollow spheroids beyond the invasive front and malignant potential of colorectal cancer.

418 Background: Hollow spheroid (HS) is a morophogenesis after budding at invasion front of colorectal cancer (CRC) tissue. HS formation of CRC cells has been shown to be induced by Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1) long cytoplasmic isoform dominance condition in three-dimensional (3D) in vitro culture. The aim of the current study is to address the existence and the clinical implication of HS in colorectal cancer. Methods: Immunohistochemical analyses were conducted with CEACAM1, CEACAM1-L, to address the existence of CEACAM1 expressing HS beyond the invasion front of CRC. The risk factors for metastases and survival were calculated using univariate and multivariate analyses on clinical samples from 164 patients with CRC. To investigate the role of HS for chemoresistance to 5-fluorouracil (5-FU), the risk factors for recurrence after adjuvant chemotherapy were calculated using univariate and multivariate analyses on clinical samples from 82 patients with Stage III CRC. R...