The detection of XXXX micrometastases in axillary lymph nodes by means of reverse transcriptase-polymerase chain reaction.

@entity1 @entity0 @entity3 @entity2355
BACKGROUND: The development of a sensitive method for the detection of @entity0 micrometastases in axillary lymph nodes is reported. METHODS: The method was based on amplification of @entity2355 mRNA, which encodes a core protein of @entity2355 , by a reverse transcriptase-polymerase chain reaction (RT-PCR). Total RNA, which was extracted from a @entity0 cell line (MCF-7), primary @entity0 , and axillary lymph nodes, was subjected to analysis of @entity2355 mRNA expression by the RT-PCR method. RESULTS: @entity2355 mRNA expression was detected by RT-PCR in MCF-7 cells and in all 15 primary @entity0 but not in control lymph nodes taken from @entity1 with benign diseases. A serial dilution study revealed that @entity2355 RT-PCR was a very sensitive method, detecting one MCF-7 cell per 1,000,000 lymph node cells. The detection sensitivity of @entity2355 RT-PCR method was compared with that of immunohistochemical staining of an epithelial marker ( @entity2355 ). Fifty axillary lymph nodes were obtained from 15 @entity1 with primary @entity0 , and @entity3 in each lymph node was investigated by both methods. The immunohistochemical method demonstrated @entity3 in nine lymph nodes, and @entity2355 mRNA was detected in all of them. Of the 41 lymph nodes that were diagnosed to be devoid of @entity3 by immunohistochemistry, @entity2355 mRNA was expressed by 6 but not by the other 35, indicating the presence of micrometastases in these 6 lymph nodes that could be detected only by the @entity2355 RT-PCR method. CONCLUSIONS: The @entity2355 RT-PCR method is more sensitive than immunohistochemistry for the detection of micrometastases in axillary lymph nodes. This new method would be of practical value in selecting the @entity1 at high risk for relapse from those who are histologically lymph node negative.
