Expression of DNA methylation-related
proteins in invasive lobular carcinoma of breast: comparison to invasive ductal carcinoma
Yoon Jin Cha, Hye Min Kim and Ja Seung Koo
Department of Pathology, Yonsei University College of Medicine, Seoul, South Korea
Offprint requests to: Ja Seung Koo, MD, PhD, Department of Pathology, Yonsei University College of Medicine, Severance Hospital, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. e-mail: firstname.lastname@example.org
Summary. Purpose: We aimed to compare the expression of DNA methylation-related proteins in invasive lobular carcinoma (ILC) of breast with those of invasive ductal carcinoma (IDC) of breast and to assess its potential clinical application.
Methods: Immunohistochemical staining of DNA methylation-related proteins (5-meC, DNMT1, DNMT3B and ISL-1) was applied to tissue microarrays generated from 108 ILCs and 203 IDCs. Protein expression and its correlation with clinicopatholgic variables were statistically analyzed.
Results: ISL-1 and DNMT3B were highly expressed in ILC (p<0.001) and tumoral 5-meC was highly expressed in IDC (p=0.006). DNMT1 (p<0.001) showed higher expression rate in luminal A type ILC. ISL-1 and DNMT3B showed higher expression rate in both luminal A type and luminal B type of ILC (p<0.05). In IDC, tumoral 5-meC commonly showed high positivity (p=0.039). On univariate analysis, shorter disease-free survival of ILC was associated with DNMT1 high positivity (p=0.001) and ISL-1 positivity (p=0.018).
Conclusion: DNA methylation-related proteins are differentially expressed in ILC and IDC, and DNMT1, DNMT3B and ISL-1 show high expression rate in ILC. Histol Histopathol 32, 1175-1185 (2017)
Key words: Breast cancer, Lobular cancer, DNA methylation, DNMT1