美國梅奧診所一項最新研究顯示,，擁有致密型乳腺和乳腺小葉未退化的女性罹患乳腺癌的風險顯著提高。

梅奧診所研究人員在新一期美國《國家癌癥研究所雜志》（JNCI）網絡版上報告說,，他們對2666名年齡在18至85歲患有良性乳腺病的婦女進行了超過13年的追蹤調查,，其間共有172名婦女患上乳腺癌。結果發(fā)現(xiàn),，致密型乳腺和乳腺小葉未退化是誘發(fā)乳腺癌的兩項獨立風險因素,。與擁有非致密型乳腺以及乳腺小葉完全退化的婦女相比，同時具有致密型乳腺和乳腺小葉未退化兩項風險因素的婦女患乳腺癌的幾率顯著提高,。

據介紹,，致密型乳腺是指乳房擁有較多的胸腺組織和導管，而脂肪含量較少,，這意味著癌細胞將有更多發(fā)展和隱藏區(qū)域,；乳腺小葉退化是乳腺上皮細胞的正常生理萎縮，并隨著年齡的增長而加快,。梅奧診所研究人員在此前一項研究中發(fā)現(xiàn),，乳腺癌變通常發(fā)生在乳腺小葉，如果乳腺小葉隨著年齡增長而逐漸退化,，婦女患乳腺癌的風險將會降低,。（生物谷Bioon.com）

生物谷推薦英文摘要：

 J Natl Cancer Inst (2010)  doi: 10.1093/jnci/djq414

Independent Association of Lobular Involution and Mammographic Breast Density With Breast Cancer Risk
Karthik Ghosh, Celine M. Vachon, V. Shane Pankratz, Robert A. Vierkant, Stephanie S. Anderson, Kathleen R. Brandt, Daniel W. Visscher, Carol Reynolds, Marlene H. Frost and Lynn C. Hartmann

Affiliations of authors:Division of General Internal Medicine, Department of Medicine (KG), Division of Epidemiology, Department of Health Sciences Research (CMV), Division of Biomedical Statistics and Informatics, Department of Health Sciences Research (VSP, RAV, SSA), Division of Breast Imaging, Department of Radiology (KRB), Division of Anatomic Pathology, Department of Laboratory Medicine and Pathology (CR), Division of Medical Oncology, Department of Oncology (MHF, LCH), Mayo Clinic, Rochester, MN; Department of Pathology, University of Michigan, Ann Arbor, MI (DWV)

Background Lobular involution, or age-related atrophy of breast lobules, is inversely associated with breast cancer risk, and mammographic breast density (MBD) is positively associated with breast cancer risk.

Methods To evaluate whether lobular involution and MBD are independently associated with breast cancer risk in women with benign breast disease, we performed a nested cohort study among women (n = 2666) with benign breast disease diagnosed at Mayo Clinic between January 1, 1985, and December 31, 1991 and a mammogram available within 6 months of the diagnosis. Women were followed up for an average of 13.3 years to document any breast cancer incidence. Lobular involution was categorized as none, partial, or complete; parenchymal pattern was classified using the Wolfe classification as N1 (nondense), P1, P2 (ductal prominence occupying <25%, or >25% of the breast, respectively), or DY (extremely dense). Hazard ratios (HRs) and 95% confidence intervals (CIs) to assess associations of lobular involution and MBD with breast cancer risk were estimated using adjusted Cox proportional hazards model. All tests of statistical significance were two-sided.

Results After adjustment for MBD, having no or partial lobular involution was associated with a higher risk of breast cancer than having complete involution (none: HR of breast cancer incidence = 2.62, 95% CI = 1.39 to 4.94; partial: HR of breast cancer incidence = 1.61, 95% CI = 1.03 to 2.53; Ptrend= .002). Similarly, after adjustment for involution, having dense breasts was associated with higher risk of breast cancer than having nondense breasts (for DY: HR of breast cancer incidence = 1.67, 95% CI = 1.03 to 2.73; for P2: HR of breast cancer incidence = 1.96, 95% CI = 1.20 to 3.21; for P1: HR of breast cancer incidence = 1.23, 95% CI = 0.67 to 2.26; Ptrend= .02). Having a combination of no involution and dense breasts was associated with higher risk of breast cancer than having complete involution and nondense breasts (HR of breast cancer incidence = 4.08, 95% CI = 1.72 to 9.68; P= .006).

Conclusion Lobular involution and MBD are independently associated with breast cancer incidence; combined, they are associated with an even greater risk for breast cancer.