Low Lamin B2 Expression Induces Nuclear Enlargement and Low Emerin Expression Results in Round Nuclei in Invasive Lobular Carcinoma of the Breast

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　　Background & Aims: Nuclear lamin and emerin play roles in nuclear morphological maintenance. Methods: In the present study, we examined the expression patterns of lamins A, B1, B2 and emerin in 17 patients with invasive lobular carcinoma (ILC) of the breast. Using computer-assisted image analysis of immunohistochemical specimens, we determined the interrogated proteins’ positive rate relative to the total number of tumor cells. Results: We found that the percentage of lamin B2-positive nuclei was negatively correlated with mean nuclear area and nuclear perimeter. Additionally, the percentage of emerin-positive nuclei was negatively correlated with mean nuclear roundness. We also found moderate positive correlations between lamin A and lamin B1and between lamin A and emerin and a strong positive correlation between lamin B1 and emerin. The percentages of emerin- and lamin B1-positive tumor cells were significantly lower in patients with triple-negative ILC than in those with luminal ILC, including luminal A, luminal B, and luminal HER2-like ILC. Conclusions: This is the first study to evaluate the association of nuclear lamins and emerin with nuclear morphology in ILC. Our analyses suggest that lamin B2 and emerin, and not lamin A and B1, are involved in altered nuclear morphologic maintenance in ILC.