Loss of PAR-3 protein expression is associated with invasion, lymph node metastasis, and poor survival in esophageal squamous cell carcinoma

Publication date: Available online 8 February 2017
Source:Human Pathology
Author(s): Tomoko Kitaichi, Kohichiroh Yasui, Yasuyuki Gen, Osamu Dohi, Naoto Iwai, Akira Tomie, Nobuhisa Yamada, Kei Terasaki, Atsushi Umemura, Taichiro Nishikawa, Kanji Yamaguchi, Michihisa Moriguchi, Yoshio Sumida, Hironori Mitsuyoshi, Yuji Naito, Yoh Zen, Yoshito Itoh
Disrupted cell polarity is a feature of epithelial cancers. The partitioning defective 3 (PAR-3) protein, a key component of the PAR complex that regulates the polarization of cells, is involved in tight junction formation at epithelial cell–cell contacts. Our previous study detected a homozygous deletion of the PAR-3 gene in esophageal squamous cell carcinoma (ESCC) cell lines and frequent copy number loss of the PAR-3 gene in primary ESCC. Here, we aimed to investigate the clinicopathological relevance of altered expression of the PAR-3 protein in primary ESCC. We immunohistochemically analyzed expression of the PAR-3 protein, as well as that of other tight junction proteins, ZO-1 and claudin-1, in 74 primary ESCCs. While the PAR-3 protein was expressed in the cytoplasm of basal cells, it was localized on the plasma membrane of suprabasal cells of normal squamous epithelium of the esophagus. Of the 74 ESCC tumors, 20 (27%), 11 (15%), and 13 (18%) were negative for PAR-3, ZO-1, and claudin-1 proteins, respectively. Negative PAR-3 protein expression, but not negative ZO-1 or claudin-1 expression, was significantly associated with deeper tumor invasion (P<.01), positive lymph node metastasis (P=.03), and advanced tumor stage (P=.01). Patients with PAR-3-negative tumors showed marginally significantly shorter overall survival after surgery than those with PAR-3-positive tumors (P=.053). In conclusion, these results suggest that PAR-3 protein expression is frequently lost in primary ESCC and that loss of the PAR-3 protein is associated with aggressive clinicopathological features of ESCC.



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