A Novel Technique for Detecting the Therapeutic Target, KRAS Mutant, From Peripheral Blood Using the Automatic Chipball Device With Weighted Enzymatic Chip Array

Reverse transcriptase and real-time polymerase chain reactions are widely used for the detection of gene overexpression. However, various disadvantages and limitations arise when the detection of multiple genetic targets is required. In previous studies, our laboratory successfully established a membrane array operation platform with a diagnostic biochip for the screening of gene overexpression by circulating tumor cells in cancer patients. To effectively shorten the reaction time, we improved the conventional RNA extraction method. The concept of weightedness was included in the reading procedure of the chip array and a weighted enzymatic chip array (WEnCA) platform was established. We used fluid engineering to develop a fully automatic gene chip analyzer named Chipball, which runs automatically on the WEnCA platform. The combination of the two systems is named the WEnCA-Chipball system. To understand the actual differences between the operations of WEnCA-Chipball and WEnCA-manual, we used the WEnCA-manual to analyze KRAS-associated gene overexpression in 200 samples from cancer patients to establish a cutoff value for activating the KRAS Detection Chip. Specifically, the activated KRAS expression in blood samples of 209 lung cancer patients was analyzed by both WEnCA-manual and WEnCA-Chipball and compared. The clinical applicability of WEnCAChipball was defined, including the sensitivity, specificity, and accuracy. The results showed that among 209 samples, 71 patients were positive for activated KRAS expression by WEnCA-Chipball with a sensitivity of 89%, specificity of 94%, and accuracy of 92%. In addition, the average total score of WEnCA-Chipball was 4.7 lower than that of the WEnCA-manual. The WEnCA-Chipball required an operation time of only 7.5 hours, approximately one-ninth of the WEnCA-manual operation time and one-fifth of the cost of WEnCA-manual. No significant difference was found between the detection limitations of the two systems. Great strides have been made in this development. The WEnCA-Chipball operation system has potential for clinical applications.