The CK7-positive and CK20-negative cohort was the most frequent (Figure 1). We found that 7 tumors did not exhibit profiles in accordance with ...BrowseSubjectAreas?ClickthroughthePLOStaxonomytofindarticlesinyourfield.FormoreinformationaboutPLOSSubjectAreas,clickhere.ArticleAuthorsMetricsCommentsMediaCoverageReaderComments(0)FiguresFiguresAbstractBackgroundDevelopmentoftailoredtreatmentbasedonimmunohistochemicalprofiles(IPs)oftumorsforcancersofunknownprimaryisneeded.Methodology/PrincipalFindingsWedevelopedanalgorithmbasedonprimaryknownadenocarcinomafortestingsensitivityandspecificity.Formalin-fixedparaffin-embeddedtissuesamplesfrom71patientsofunfavorablesubsetsofunknownprimaryadenocarcinomawereobtained.Weexamined15molecularmarkersusingthealgorithmincorporatingtheseIPsandclassifiedthetumoursinto9subsetsbasedontheprimarytumoursite.Thesensitivityandspecificityofthisalgorithmwere80.3%and97.6%,respectively.Apparentprimarysiteswerelungin17patients,digestiveorgansin13,gynecologicalorgansin9,prostatein7,liverorkidneyin6,breastin4,urothelialorganin2,biliarytractandpancreaticprofileinnone,andunclassifiedin13.TheresponseratetochemotherapywashighestforthegynecologicalIPs.PatientswithgynecologicalorlungcancerIPshadlongermedianprogression-freesurvivalthanthosewithothers:11.2monthsforgynecologicalIPs(p<0.001)and6.8monthsforlungIPs(p = 0.05).Lung,digestive,prostate,andgynecologicalprofileswereassociatedwithsignificantlylongermediansurvivaltimethantheotherprofiles.MultivariateanalysisconfirmedthattheIPswereindependentprognosticfactorsforsurvival.Conclusions/SignificanceTheIPsidentifiedinthisstudycanbeusedtofurtherstratifypatientprognosisforunfavorablesubsetsofunknownprimaryadenocarcinoma.Citation:HashimotoK,SasajimaY,AndoM,YonemoriK,HirakawaA,FurutaK,etal.(2012)ImmunohistochemicalProfileforUnknownPrimaryAdenocarcinoma.PLoSONE7(1):e31181.https://doi.org/10.1371/journal.pone.0031181Editor:SyedA.Aziz,HealthCanada,CanadaReceived:August12,2011;Accepted:January3,2012;Published:January27,2