Conventional cancer diagnosis needs to excise diseased tissue from the
patient's body for biopsy, causing severe injury to patients. Liquid
biopsy with the superior advantage of minimal invasiveness has shown its
ability to cancer diagnosis in real-time, and has been developing
promising diagnostic instruments. However, until today, the developed
instrument still cannot be an alternative to tissue biopsy in the
majority of research and clinical settings. In this paper, we firstly
summarize the challenges and limitations suffered by the existing liquid
biopsy instrument. Then, the opportunities and future progression of the
next-generation instrument are discussed in detail. In all, we hope that
the future liquid biopsy instrument can be eventually integrated into
the clinical workflow, and serve as a validated and reliable tool for
cancer diagnosis.