{"entity":{"id":"cldn6","kind":"target","name":"Claudin 6","aka":[],"tldr":"A tight-junction protein normally found only in the embryo that reappears in ovarian, testicular, endometrial and lung cancers, making it a clean target for ADCs and CAR-T.","summary":"Claudin 6 is an oncofetal antigen essentially absent from adult tissue, unlike its relative CLDN18.2 (gastric mucosa). It is expressed in ~50-60% of ovarian and testicular germ cell tumours, and subsets of endometrial, lung and gastric cancers. TORL-1-23 (ADC) is in phase 2/3 in ovarian cancer; BNT211 (CAR-T with an amplifying mRNA vaccine, CARVac) reported responses in germ cell tumours; DS-9606 is another ADC. Sequence similarity to CLDN9 and CLDN4 requires highly selective antibodies.","asOf":"2026-09-08","wikipedia":"https://en.wikipedia.org/wiki/CLDN6","links":[{"label":"BNT211 CARVac (Nat Med 2023)","url":"https://doi.org/10.1038/s41591-023-02612-0"}],"tags":["gap-fill"],"related":["cldn18-2"],"cancers":["ovarian","testicular","endometrial","nsclc"],"sections":[],"technologies":["adc","car-t","neoantigen-mrna-vaccine"],"targets":[],"drugs":[],"companies":["biontech","daiichi-sankyo"],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":["paper-mackensen-nat-med"],"journals":[],"dependsOn":[],"notes":[],"symbol":"CLDN6","role":[],"sources":[],"specificitySources":[],"hgnc":"HGNC:2048","ensembl":"ENSG00000184697","uniprot":"P56747","entrez":"9074","firstDescribed":1999,"firstDescribedBasis":"sequence","firstDescribedNote":"Earliest sequence paper UniProt cites for the protein: Keen T.J. et al, 1999.","firstDescribedSource":"https://www.uniprot.org/uniprotkb/P56747/entry","biology":"Four-transmembrane tight-junction claudin expressed in embryonic epithelia and germ cells; silenced after development, re-expressed in cancers via epigenetic derepression.","whereFound":["Ovarian cancer (~50-60%)","Testicular germ cell tumours (>90%)","Endometrial cancer (~30%)","NSCLC adenocarcinoma and gastric cancer (subsets)"],"targetClass":"surface-antigen","prevalence":[{"cancerId":"ovarian","pct":"50-60","measure":"IHC positivity","note":"varies by antibody and cutoff"},{"cancerId":"testicular","pct":"90","measure":"IHC positivity"}]},"route":"/targets/cldn6/","neighbours":{"target":[{"id":"cldn18-2","kind":"target","name":"Claudin 18.2","route":"/targets/cldn18-2/"}],"cancer":[{"id":"endometrial","kind":"cancer","name":"Endometrial cancer","route":"/cancers/endometrial/"},{"id":"nsclc","kind":"cancer","name":"Non-small-cell lung cancer","route":"/cancers/nsclc/"},{"id":"ovarian","kind":"cancer","name":"Ovarian cancer","route":"/cancers/ovarian/"},{"id":"testicular","kind":"cancer","name":"Testicular germ cell tumours","route":"/cancers/testicular/"}],"technology":[{"id":"adc","kind":"technology","name":"Antibody-drug conjugate (ADC)","route":"/technologies/adc/"},{"id":"car-t","kind":"technology","name":"CAR-T cell therapy","route":"/technologies/car-t/"},{"id":"neoantigen-mrna-vaccine","kind":"technology","name":"Personalised neoantigen (mRNA) vaccines","route":"/technologies/neoantigen-mrna-vaccine/"}],"company":[{"id":"biontech","kind":"company","name":"BioNTech","route":"/companies/biontech/"},{"id":"daiichi-sankyo","kind":"company","name":"Daiichi Sankyo","route":"/companies/daiichi-sankyo/"}],"paper":[{"id":"paper-mackensen-nat-med","kind":"paper","name":"CLDN6-specific CAR-T cells plus amplifying RNA vaccine in relapsed or refractory solid tumors: the phase 1 BNT211-01 trial","route":"/key-papers/paper-mackensen-nat-med/"}]}}