Altered intracellular region of MUC1 and disrupted correlation of polarity-related molecules in breast cancer subtypes.
Bottom Line: Localization of MUC1 protein varied among breast cancer subtypes, that is, both the apical domain and cytoplasm in luminal A-like tumors (P < 0.01) and both the cytoplasm and cell membrane in luminal B-like (growth factor receptor 2 [HER2]+) tumors (P < 0.05), and no expression was found in triple negative tumors (P < 0.001).The incidence of mutual correlations of expression levels between two of the 10 molecules (55 combinations) was 54.5% in normal breast tissue and 38.2% in luminal A-like specimens, 16.4% in luminal B-like (HER2+), 3.6% in HER2 and 18.2% in triple negative specimens.In conclusion, each breast cancer subtype has characteristic cytoplasmic localization patterns of MUC1 and different degrees of disrupted correlation of the expression levels between the 10 examined molecules in comparison with normal breast tissue.
Affiliation: Department of Breast and Endocrine Surgery, Nihon University School of Medicine, Tokyo, Japan.Show MeSH
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Mentions: We examined correlations between molecules in all 55 combinations, of which 30 of the 55 pairs (54.5%) were correlated significantly and well maintained in normal breast tissues (Table5), but decreased to 21/55 pairs (38.2%) in luminal A-like (no significant difference compared with 54.5% in normal breast tissue), 9/55 (16.4%) pairs in luminal B-like (HER2+) (P < 0.001), 2/55 (3.6%) pairs in HER2 (P < 0.001) and 10/55 (18.2%) pairs in TN (P < 0.001) breast tumors (Table5; Fig.3). Because we only had two luminal B-like (HER2−) cases, this subtype was not examined in the correlation analysis. All subtypes except for luminal A-like had disrupted cell polarity with moderate (TN) or severe (luminal B-like [HER2+], HER2) degrees according to the criteria described in the Materials and Methods. Representative correlations between the molecule pairs are shown in Fig.4, and their significant correlations are schematically presented in Fig.5. Expression of AJ-TJ-Rho-Par was positively correlated to normal breast tissue, TJ-Rho-Par were partially correlated to luminal A-like, and only incomplete correlations were found in the other types (Fig.5).
Affiliation: Department of Breast and Endocrine Surgery, Nihon University School of Medicine, Tokyo, Japan.