CPC C12Q 1/6886 (2013.01) [C12Q 2600/156 (2013.01)] | 7 Claims |
1. A method for detecting in a patient the presence of a exosomal biomarker, comprising:
(a) drawing a peripheral blood sample from a patient having pheochromocytoma or paraganglioma;
(b) centrifuging the sample at 3,000-5,000 rpm to collect serum at 4° C.;
(c) centrifuging the collected serum again at 3,000-5,000 rpm to obtain a supernatant;
(d) centrifuging the supernatant at 100000 g-120000 g, washing and re-suspending the resulting precipitate to obtain an exosome sample;
(e) treating the exosome sample with DNase I;
(f) digesting the treated exosome sample with RNase A to digest external RNA;
(g) chelating the RNase A-digested exosome sample with EDTA;
(h) digesting the exosome sample from step (g) with proteinase K at 50-60° C. for 5-20 min in accordance with the volume ratio of the exosome sample and proteinase K of 1:20-100 to digest the DNase I, RNase A and other external proteins to obtain a nucleic acid sample; and
(i) identifying the nucleic acid sample for the presence or absence of a biomarker, wherein the biomarker contains at least one double-stranded DNA fragment having a variation of SDHB and the variation is the c.281 G>A mutation in the SDHB coding sequence.
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