An　increasingly　branched　rolling　circle　amplification　(IB-RCA)　which　contains　a　padlock　probe　(PP)　and　a　structurally　tailored　molecular　beacon　(MB)　was　innovatively　developed　for　highly　sensitive　detection　of　cancer　gene,　Kras　gene　codon　12.　In　this　system,　the　PP　can　be　circularized　after　hybridization　with　the　precisely-matched　target　DNA,　while　the　stem　of　MB　can　be　also　opened　by　target　DNA,　resulting　in　hybridization　with　the　circularized　PP　to　generate　a　long　tandem　single-stranded　DNA　(ssDNA)　product.　Since　the　MB　is　also　designed　to　hybridize　with　ssDNA　product,　the　newly-opened　MBs　are　able　to　trigger　the　next　RCA　reactions,　therapy　producing　branched　rolling　circle　amplification　(RCA)　products　and　in　turn　leading　to　the　increasingly　branched　RCA　(IB-RCA).　This　alternately　and　continuously　operates　hybridization-based　MB　opening　and　opened　MBs-triggered　RCA.　As　a　result,　a　great　number　of　MBs　are　opened　that　is　associated　with　a　dramatically　amplified　fluorescent　signal,　enabling　to　quantify　target　DNA　down　to　100　fM.　This　sensing　method　demonstrates　a　new　concept　of　IB-RCA　amplification　even　in　a　simple　way　to　efficiently　transduce　the　fluorescence　signal,　accomplishing　the　highly　sensitive　and　selective　detection　of　cancer　gene.　(C)　2016　Elsevier　B.V.　All　rights　reserved.