Detection failure of BRAF V600E by Oncomine Dx Target Test in Lung Cancer

M. Inagaki*^a (Dr)

^a Tsuchiura Kyodo General Hospital, Tsuchiura, JAPAN

* masaharu_inagaki@yahoo.co.jp

Subjects and methods: Of the 123 cases in 2019-2020, 44 cases could were inadequate, 14 cases could not be determined) were examined.

Results: All 14 undecidable cases were biopsy specimens. The size of the sample is 2*2 mm or more (6 cases), less than 1*1 mm(3 cases), and the middle(5 cases). Specimens including necrosis and crush(7 cases),specimens with conspicuous bleeding(4 cases), adenocarcinoma with preserved airspace(1 case).Of the 14 cases that could not be determined, in 8 cases in 2020, when an inquiry was made to the inspection company and an answer was obtained, PCR amplification failure was 6 cases, and read amplicon non-uniformity was 2 cases. It was considered that the cause was insufficient formalin fixation ad poor nucleic acid condition due to formalin over fixation. Regarding the lack on volume of 2*2 mm or more in the first HE, and it is possible that the sample volume was insufficient due to slicing, but it could no be verified.

Discussion: Shortening the time from the collection of biopsy specimens to the start of formalin fixation and management of the fixation start time, Class5 cytopathology LBC specimens can be stored in cell blocks and used for testing. Exchange opinions and collaborate closely with clinicians when submitting a cancer genome test. Discussion when the amount is insufficient or the judgment cannot be made. Measures such as inspection result monitoring are required

Disclosure of funding source(s): none