Effect of lamins and emerin on nuclear morphology and histological architecture in lung adenocarcinoma

Emerin and lamins not only influence nuclear morphology but are also involved in differentiation. We herein examined 82 resected cases of invasive lung adenocarcinoma using computer-assisted image analysis of nuclear morphology on Feulgen-stained and immunohistochemical sections of lamin A, B1, B2, and emerin (four proteins) to calculate the rank sum of the cell positivity rates for these four proteins. The rank sum of four proteins showed weak negative correlations with the nuclear area and perimeter and a weak positive correlation with the nuclear shape factor. Interestingly, the top three cases with the highest rank sum were papillary adenocarcinoma, and the bottom three cases were acinar adenocarcinomas containing cribriform patterns. We compared the rank sum for grading (differentiation: G1, G2, and G3) and predominant histological subtypes and found that the rank sum of G3 was lower than that of G1 and G2. Furthermore, the rank sum was lower for acinar adenocarcinoma with >20 % cribriform pattern (acinar+cribri) and solid adenocarcinoma than for lepidic and papillary adenocarcinoma. Individual examination of the four proteins revealed that emerin expression was lower in G3 than in G1, and lamin B2 expression was lower in G3 than in G1 and G2. Compared with lepidic adenocarcinoma, acinar+cribri showed significantly lower expression of all four proteins among histological subtypes. These data indicated that the expression of lamin A, B1, B2, and emerin was markedly decreased in poorly differentiated adenocarcinoma (i.e., G3), especially in acinar+cribri. Our data suggested that changes in these four proteins can not only affect nuclear morphology but also histological structure in lung adenocarcinoma.