Abstract: Objective : The gene prolactin-inducible protein (PIP/GCDPFIS) is believed tooriginate from a limited set of tissues, including breast and has been applied as a clinical markerof human breast cancer metastasis. We examined PIP mRNA expression as a marker for the de-tection of carcinoma cells by reverse transcription polymerase chain reaction (RT-PCR). Meth-ods : Total RNA, which was extracted from 44 primary breast carcinomas and correspondling nor-mal tissues, and 25 other carcinomas (including gastric carcinoma, esophageal carcinoma, lung carcinoma, ovary carcinoma and carcinoma of the large intestine) was subjected to analysis of PIPmRNA expression by the RT-PCR. The relationships between clinicopathological characteristics ofthe patients and the results of RT-PCR was analyzed by statistics. Results : PIP mRNA ex-pression was detected by RT-PCR in 43 of 44 breast carcinomas. In the analysis,PIP mRNA levels were decreased relative to normal breast tissue in 69.8% (30/43) of cases. there were 2positive in 25 other cancers. There is obviously different between breast cancer and other cancersin the expression of the PIP gene (P<0.01). There is no relationship between the expression of the PIP gene and the stage and the statuses of PR and PR of the patients (P>0.05) Conclusion :Whether PIP mRNA can be a marker in the detection of mierometastasis of breast caneer de-pends on further study.