> Scientists say a new handheld device is capable of testing for breast cancer in less than five seconds using just a small sample of saliva

Second sentence in the the linked post

So, reading an actual publication [1], all this test does is identify if the patient has the BRCA biomarker for breast cancer. It doesn't actually detect if the patient has breast cancer. The title is misleading, as is your post.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9249990/