Abstract: Objective To investigate the pathomorphology ，biologic characteristics and the relation?ships of triple-negative breast cancer (TNBC)，non triple-negative breast cancer(NTNBC) and basal like breast cancer（BLBC）. Methods HER2 ，ER，PR，CK5 / 6 or EGFR protein were determined with immunohistochemistry（IHC ）in breast cancer, 3 cases of HER 2 IHC 3 + and 5 cases of HER2 IHC 2 + were analysed for HER2 gene amplification with fluorescent in situ hybridization（FISH）. CK5 / 6 or EGFR were checked in 22cases of TNBC. The cases were divided into the TNBC，NTNBC and BLBC groups according to the examination results.The pathomorphology and biologic characteristics of the three groups were compared. Results Of the 96cases，27. 08% （26/96）were confirmed to be TNBC in which grade Ⅱand Ⅲ caseswere 53. 85%（14/ 26）and 46. 15%（12/26）respectively ，lymph nodes metastasis rate was 61. 11%（11/ 18）；BLBC accounted for63. 64%（14/22）of TNBC ，in which grade Ⅱand Ⅲcases were 57. 14%（8 / 14）and 42. 86%（6 / 14）respectively ，lymph nodes metastasis rate was 55. 56%（5 / 9）；There were no grade Ⅰcases in TNBC andBLBC. 7 2 . 92%（70/ 96）wereconfirmedtobeNTNBCinwhichgradeⅠ，Ⅱand Ⅲcaseswere 28. 57%（20/ 70），57. 14%（40/ 70）and 14. 29%（10/ 70）respectively ，lymph nodes metastasis rate was 44. 44%（16/36）. The percentage of poorly differentiated cases and lymph nodes metastasis rate were higher inthe TNBC and BLBC group than those in NTNBC ，besides there was no gradeⅠcases in TNBC andBLBC group. Of the 5 HER2 IHC 2 + cases，one case there was gene amplification ，one equivocaland threenegativeand of 3 HER2 IHC 3 + cases,theFISH resultwasconsistentwith IHC.Conclusion More than 1 / 4 of breast cancer are TNBC or BLBC in our study.Compared with NTNBC，eventhough TNBC and BLBC share agreat dealof overlap and have a poor differentiation with aggressive behavior and increased local recurrence or distant metastasis，indicating a poor prognosis，theymaybe independent histopathologic entity. CK 5 / 6 or EGFR can be used to differentiate the BLBC fromTNBC.IHC 2 +cases should be examined with FISH in order to avoid misleading treatment.

Key words: triple-negativebreastcancer, basal-likebreastcancer, pathomorphology, FISH