***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Proliferative lesions of the mammary gl and are risk markers and potential precursors for the development of breast cancer in postmenopausal women . In this study we evaluated mammary epithelial proliferation and proliferative lesions in a group of 63 aged postmenopausal macaques r and omized by social group to receive one of three experimental diets for 8 months : ( 1 ) control ; ( 2 ) control with 17β-estradiol ( E2 ) at the human equivalent dose of 1.0 mg per day ; and ( 3 ) control with the soy phytoestrogen equol ( EQ ) at the human equivalent dose of 105 mg per day . In normal mammary epithelium , treatment with E2 but not EQ result ed in greater proliferation , epithelial area , and progesterone receptor expression ( P<0.05 for all ) . Mammary lesions included columnar cell change ( 26/63 ) , columnar cell hyperplasia with and without atypia ( 13/63 ) , atypical ductal hyperplasia ( 6/63 ) , and atypical lobular hyperplasia ( 3/63 ) . Lesions were most common within terminal ductal lobular units . The prevalence of columnar cell hyperplasia ( total and atypical cases ) was higher in animals treated with E2 compared to control ( P<0.05 for both ) . Compared to normal mammary epithelium , columnar cell lesions ( CCLs ) showed greater constitutive expression of estrogen receptor-α across all groups ( P<0.001 ) and greater expression of progesterone receptor in response to E2 ( P<0.01 ) . Independent of treatment , animals with CCLs on histology had greater gene expression of estrogen receptor-α and markers of estrogen receptor activity ( trefoil factor 1 ) and proliferation ( gene for Ki67 antigen ) at a site contralateral to the CCL ( P<0.05 for all ) . These findings demonstrate that the terminal ductal lobular units of the postmenopausal mammary gl and contain morphologically distinct cell population s that may hyperrespond to E2 exposure , result ing in specific types of hyperplastic lesions 
    Output:
    
For CCL without atypia , more studies with a long-term follow-up are required , but so far , surgical excision biopsy does not seem to be necessary