Insitu hybridisation andS1mapping showthatthepresence of infiltrating plasma cells isassociated withpoorprognosis inbreast cancer

SummaryInorder toidentify potential markers ofprognosis inbreast cancer, representative cDNAlibraries wereconstructed using RNA isolated fromprimary breast tumourtissue associated withgoodandpoor prognosis. Cross-screening ofthese libraries repeatedly identified cloned mRNA species associated withthe immunesystem, inparticular B-cells, inlibraries derived fromtumours ofpoorprognosis. We haveusedone ofthese, aKIVlight chain cDNAprobe, intwocomplementary studies toinvestigate therelationship between immunoglobin geneexpression andprognosis. Theresults obtained using acombination ofS,mapping, RNA blotting andinsitu hybridisation demonstrate thatthepresence ofplasma cells, asdefined byinfiltrating cells whichexpress highlevels ofimmunoglobulin K-chain mRNA,isassociated withapoorprognosis. A large proportion ofwomen withoperable primary breast cancer haveoccult micrometastases at presentation. The mostaccurate indicator ofthepresenceofmetastases isthe extentofaxillary lymphnodeinvolvement assessed by a pathologist after complete axillary dissection. Howeverthe