Collapsin response mediator protein 2 is involved in regulating breast cancer progression
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Altered expression of collapsin response mediator proteins (CRMPs) has been reported in several malignant tumors, including downregulation of CRMP1 in lung cancer and upregulation of CRMP2 in colorectal cancer. This study aimed to investigate the relationship between CRMP expression and clinicopathological characteristics in patients with breast cancer.
Twenty-two breast cancer and four normal breast tissues were used to assess CRMP mRNA expression. The average expression level of each CRMP (CRMP1–5) mRNA was analyzed in a subset of breast cancer specimens and compared with that in normal breast tissue by real-time quantitative reverse-transcription polymerase chain reaction. Furthermore, 173 breast cancer specimens and matching normal breast controls were used for immunohistochemistry based on the tissue microarray technique. Levels of CRMP2 and phosphorylated CRMP2 protein were assessed, and possible correlations between the clinicopathological characteristics were evaluated.
The expression of CRMP2 mRNA was significantly decreased in breast cancer tissues, while that of the other CRMPs was similar between normal and breast cancer tissues. Immunohistochemistry revealed that CRMP2 protein expression was also decreased in breast cancer tissues (P < 0.001). Phosphorylated CRMP2 was observed in the nuclei of breast cancer cells but not in normal mammary cells (P < 0.001). Furthermore, nuclear phosphorylated CRMP2 expression was increased in proportion to the histological grade and triple-negative subtype.
Reduced CRMP2 expression and elevated expression of nuclear phosphorylated CRMP2 may be associated with breast cancer progression.
KeywordsBreast cancer Collapsin response mediator protein 2 Nuclear localization Microtubule Triple-negative breast cancer
We thank Msato Kodera, Harumi Sakurada, Yuka Honjoh, Makiko Fujimura and Yumi Inada for their technical and secretarial assistance. We also thank the staff of the Human Cancer Tissue Center of Kanagawa Cancer Research and Information Association for preparation of tissue samples and clinicopathological information. This study was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science under the Ministry of Education, Culture, Sports, Science and Technology (Fundamental Research: C, 23591899) (to Takashi Ishikawa, no. 80275049).
Conflict of interest
The authors declare that they have no conflict of interests.
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