Mutation　of　p53　tumor　suppressor　gene　represents　one　of　the　early　molecular　events　in　tumor　initiation　and　progression.　Although　molecular　computing　holds　tremendous　potential　with　important　applications　in　diagnosis,　prognosis　and　treatment　of　human　diseases　at　the　molecular　level,　designing　molecular　logic　gates　to　implement　cascade　amplification　via　operating　autonomously　for　the　detection　of　point　mutations　still　remains　challenging.　In　this　contribution,　we　developed　a　three　concatenated　logic　gates　(TCLG)　to　perform　multiple　strand　displacement　amplification　(m-SDA)　for　screening　the　cancer-related　point　mutations　only　via　designing　an　innovative　molecular　beacon　(MB).　Specifically,　using　p53　gene　as　model　target,　extending　the　two　ends　of　a　MB　via　adding　two　fragments　with　the　same　sequence　achieves　two　unique　terminal　single-stranded　(ss)　overhangs.　After　self-folding　of　MB　into　hairpin　structure,　the　two　overhangs　exhibit　a　near　inverted　mirror　image　(IM)　relationship　if　taking　the　base　nature　and　direction　into　account.　For　this,　the　probe　is　called　IM-MB.　Because　cascade　SDAs　can　occur　on　IM-MB　and　promote　each　other,　the　target　gene　can　be　detected　down　to　10　pM.　Along　this　line,　the　TCLG　circuit　was　proposed,　and　two　primers　and　target　gene　serve　as　the　indispensable　input　signals.　Utilizing　this　logic　circuit,　the　point　mutation　or　absence　of　target　gene　can　be　sensitively　screened.　Moreover,　its　potential　application　in　the　recognition　of　point　mutations　in　complex　biomatrix　has　been　demonstrated　via　blind　test.　The　proof-of-concept　scheme　is　expected　to　provide　new　insight　into　the　development　of　DNA-based　molecular　logic　gates　and　their　applications　in　basic　research,　medical　diagnosis　and　precise　treatment　and　treatment　of　genetic　diseases.　©　2018　Elsevier　B.V.