The Expression And Significance Of P63, α-SMA And Calponin Proteins In Benign And Malignant Lesions Of Breast

Objective: To investigate the expression and significance of P63,α-SMAand Calponin proteins in benign and malignant lesions of breast. Methods: 67cases of breast carcinoma, containing normal breast tissues,usual hyperplasiaand atypical ductal hyperiplasia(ADH),were selected .According to the critieriafrom Diagnostic surgical pathology, 3rd edition, these pathological changes weredivided into 5 groups , the expression of P63,α-SMA and Calponin weredetected by immunohistochemistry in each group. Rusults: In normal breast tissues group, usual hyperplasia and atypicalductal hyperiplasia groups, P63 ,α-SMA and Calponin were positive inalmost all of the myoepithelial cells, and the above antibodies were negative in allthe breast epithelial cells; In the carcinoma in situ group , P63,α-SMA andCalponin showed:some cancer cell nests showing continuous positivemyoepithelial cells ( MECs ) in their circumference ,others showingdiscontinuous positive MECs or entirely no positive MECs; It was no P63 orα-SMA or Calponin positive myoepithelial cells in invasive carcinomagroup ,Tumor cells in 2 invasive carcinomas of 67cases showed focal P63positive expression. no case showed p63 expression in myofibroblasts or vascularsmooth muscle cells ,whereas all cases showed α-SMA positive expression and afew cases showed Calponin positive expression in myofibroblasts or vascularsmooth muscle cells.expression of P63 and Calponin in four groups (containingnormal breast ,usual hyperplasia,ADH and carcinoma in situ) showed nosignificant difference, respectively;expression of α-SMA in three groups(including normal breast ,usual hyperplasia and ADH) had no significantdifference,Nevertheless presented significant difference compared withcarcinoma in situ group. Conclusion: Although antibodies to P63 offer excellent sensitivity andincreased specificity for myoepithelial cell detection relative to antibodies toCalponin andα-SMA,they have the following diagnostic limitations: ① they reacted with a small subset of breast carcinoma tumor cells; ② Some apparently myoepithelial cells occasionally showed P63 negative ; ③ It canoccasionally be challenging to discern the difference between the "dotted line" ofnuclei of normal p63-defined MECs layer and the disrupted line of lost MECsnuclei in breast lesions. These defects could cause diagnosticdifficulty .Therefore ,the detection of P63 with simultaneous assay of α-SMA/Calponin could help us to recognize myoepithelial cells correctly in confusingbreast lesions.