Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

$5 device tests for breast cancer in under 5 seconds: study

studyfinds.org

Post reply on HN
Print view View original

71–80 of 137 posts

Re: $5 device tests for breast cancer in under 5 seconds: study

#71

Post by [deleted] »

shelkie wrote: post #25
Ginger-Pickles wrote: post #19

Earlier quoted context omitted.

First standout thing I noticed is the “patern generator” array of DIPs - admittedly without having dived into the paper, any answers from the hive mind what they’re doing?

Breast cancer is a terrible disease, and I don't mean to be a downer but my BS detector is screaming on this one. I'd give the device image a pass if were just a journalist grabbing a stock PCB image, but that doesn't seem to be the case here. Anyone with even a trivial knowledge of electronics would be amused by the callouts. And all for just $5? After Theranos I guess I'm a bit sceptical of claims such as this.

[deleted]

Re: $5 device tests for breast cancer in under 5 seconds: study

#72

Post by lofatdairy »

hn_throwaway_99 wrote: post #64
jncfhnb wrote: post #57

Earlier quoted context omitted.

You can absolutely draw conclusions about the statistical power of the test. That’s what statistics is for. If this sample data is randomly sampled it looks like it will be a fairly high precision test for invasive cancers, with room for false negatives. You would have had to have gotten very unlucky to see such a difference in distributions even on a small sample like this. But sure, let’s get more samples.

Thank you for this! I get frustrated with the "N of only 21? Might as well flip a coin!" responses. Like you say, the whole purpose of statistical testing is to give an accurate, numeric value that says how likely the results are due to chance. One thing I'd note, though, is that the paper's title is "High sensitivity saliva-based biosensor in detection of breast cancer biomarkers: HER2 and CA15-3". My understanding…

Sensitivity matters in this case because the medium is saliva which contains a fraction of the antigens contained in serum. Specificity is challenging when the biomarkers are non-specific and you only have 1 testing modality but that seems to be not so much the case here.

Re: $5 device tests for breast cancer in under 5 seconds: study

#73

Post by ethanbond »

matthewmacleod wrote: post #69
oliwarner wrote: post #61

Earlier quoted context omitted.

It's only as harsh as the the headline is rose-tinted. "Exploratory study shows promise" is better. When n=21, flipping a coin as about as accurate.

This statement belies a fundamental misunderstanding of statistics on your part.

If you're really good at statistics, you can just intuit what seems like a sufficient N. This is actually a powerful statistical method because you can vary your intuition depending on whether you want to believe the study was well-powered or not, enabling you to easily discard Bad Evidence and include Good Evidence.

Few understand this.

Re: $5 device tests for breast cancer in under 5 seconds: study

#74

Post by lofatdairy »

yakito wrote: post #24

As a reference. Currently an MRI scan can go from $400-$2000 (mostly covered by insurance) https://scan.com/body-parts/breast An MRI machine cost arounds $350.000 on average. https://www.blockimaging.com

Better reference would be an ELISA test (which is actually brought up as the reference in the paper)[^1]. That seems to also run about $5 per kit per antigen[^2]. However this device seems to only require the test strip to be replaced, whereas you can only run ELISA once per strip/reagents. Also note that ELISA is harder to run so you have personnel costs and also this device claims higher sensitivity.

[^1]: https://pubs.aip.org/avs/jvb/article/42/2/023202/3262988/Hig...

[^2]: https://www.thermofisher.com/elisa/product/ErbB2-HER2-Human-..., note that I didn't shop around for necessarily the best prices.

Re: $5 device tests for breast cancer in under 5 seconds: study

#75

Post by DoreenMichele »

The biosensor, a collaborative development by the University of Florida and National Yang Ming Chiao Tung University in Taiwan, employs paper test strips coated with specific antibodies. These antibodies interact with cancer biomarkers targeted in the test. Upon placing a drop of saliva on the strip, electrical pulses are sent to contact points on the biosensor device. This process leads to the binding of biomarkers to antibodies, resulting in a measurable change in the output signal. This change is then converted into digital data, indicating the biomarker’s presence.

It tests for biomarkers in the saliva. Possibly not outright crazy charlatan territory.

Could certainly use a larger sample size though, especially given that one of its bragging points is "fast and cheap!"

Re: $5 device tests for breast cancer in under 5 seconds: study

#76

Post by adamredwoods »

>> HER2 and/or CA15-3 in serum are essential biomarkers used in breast cancer diagnosis.

This is WRONG, it is used as an indicator, NOT a diagnosis. In fact, I have personal experience that CA15-3 is not always in indicator of anything. You first measure a baseline, and use it for reference.

Also there's no HER2 expression in TNBC.

Can this be used for possible early detection? Maybe, but it will not be an exact science.

Re: $5 device tests for breast cancer in under 5 seconds: study

#77

Post by jncfhnb »

hn_throwaway_99 wrote: post #64
jncfhnb wrote: post #57

Earlier quoted context omitted.

You can absolutely draw conclusions about the statistical power of the test. That’s what statistics is for. If this sample data is randomly sampled it looks like it will be a fairly high precision test for invasive cancers, with room for false negatives. You would have had to have gotten very unlucky to see such a difference in distributions even on a small sample like this. But sure, let’s get more samples.

Thank you for this! I get frustrated with the "N of only 21? Might as well flip a coin!" responses. Like you say, the whole purpose of statistical testing is to give an accurate, numeric value that says how likely the results are due to chance. One thing I'd note, though, is that the paper's title is "High sensitivity saliva-based biosensor in detection of breast cancer biomarkers: HER2 and CA15-3". My understanding…

Well, depends. It’s bayes law fucking us over with the vast majority of people not having breast cancer but really, really needing to know if they do.

This is why it’s better to have tiers of confidence for actual policy decisions and not just confusion matrix results frankly.

Like if you run this test and you’re in a cohort that is 99.999% likely to be cancer, that’s useful info. It’s not a problem, per se, if the test instead comes back with an answer of mixed certainty. We just need to be comfortable with getting neither a positive nor a negative prediction; nor expecting it to cover all cases.

The policy driving thresholds on tests need to consider the weights of each possible outcome to determine what to do.

Re: $5 device tests for breast cancer in under 5 seconds: study

#78

Post by kenjackson »

jncfhnb wrote: post #57
e63f67dd-065b wrote: post #12

Press release: https://publishing.aip.org/publications/latest-content/would... Actual publication: https://pubs.aip.org/avs/jvb/article/42/2/023202/3262988/Hig... Experiment size is literally N=21, with 4 healthy participants, 3 in-situ breast cancers, and 14 invasive breast cancers. N=21 might as well be useless in my opinion. You can't draw any meaningful conclusions about statistical power of this test; if your pr…

You can absolutely draw conclusions about the statistical power of the test. That’s what statistics is for. If this sample data is randomly sampled it looks like it will be a fairly high precision test for invasive cancers, with room for false negatives. You would have had to have gotten very unlucky to see such a difference in distributions even on a small sample like this. But sure, let’s get more samples.

And this result probably helps the funding to get more patients. I’ve never worked in clinical trials but it seems like it would be so tiresome.

Re: $5 device tests for breast cancer in under 5 seconds: study

#79

Post by neuronexmachina »

e63f67dd-065b wrote: post #12

Press release: https://publishing.aip.org/publications/latest-content/would... Actual publication: https://pubs.aip.org/avs/jvb/article/42/2/023202/3262988/Hig... Experiment size is literally N=21, with 4 healthy participants, 3 in-situ breast cancers, and 14 invasive breast cancers. N=21 might as well be useless in my opinion. You can't draw any meaningful conclusions about statistical power of this test; if your pr…

> Table I shows the median and the range of digital readings by disease status and overall p-value using the Kruskal–Wallis test to examine if there exist statistically significant distinctions among two or more groups. The overall p-value is significant while the value for HER2 is 0.002, which show the probability of false-positive detection. This indicates that this sensor technology is an efficient way to detect HER2 biomarkers in saliva.

> ... In Fig. 5, the test results for detecting CA15-3 of the human samples are displayed. The digital reading decreases from the healthy group to the invasive breast cancer group, indicating an increase in CA15-3 concentration. The median, the range by disease status, and overall p-values analyzed with the Kruskal–Wallis test for the CA15-3 test are listed in Table I. The overall p-value for CA15-3 is 0.005, indicating that this device provides an efficient way to detect the salivary biomarkers related to breast cancer.

Re: $5 device tests for breast cancer in under 5 seconds: study

#80

Post by neuronexmachina »

rainbowzootsuit wrote: post #16
zacharyvoase wrote: post #10

> The study is published in the Journal of Vacuum Science & Technology B Dare I ask why?

Thin films grown in vacuums are how you get graphene layers and FETs that appear to be the basis of the technology here. Someone with a vacuum deposition system would be the prime candidate to develop a custom thin film to target adsorption of the molecules that they're trying to sense.

This part of the study describes what they implemented:

>Instead of using the transistors as the sensors, which need to be disposed of after each use, a system with a reusable printed circuit board (PCB) containing a MOSFET and disposable test strips were employed. In this approach, synchronized double-pulses were applied at the gate and drain terminals of the transistor to ensure that the channel charge does not accumulate, and there is no need to reset the drain and gate paths to mitigate the charge accumulation at the gate and drain of the sensing transistor for sequential testing. With the double-pulse approach, it only takes a few seconds to show the result of the test, due to the rapid response of the functionalized test strips and resulting electrical signal output. As an example, the LoD has been demonstrated to reach 10−15 g/ml and the sensitivity to 78/dec for COVID-19 detection. Similar approaches have been used to detect cerebrospinal fluid (CSF), cardiac troponin I, and Zika virus.27–30

> In this work, use of this double-pulse measurement approach to detect HER2 and CA15-3 in saliva samples collected from healthy volunteers and breast cancer patients was investigated. The voltage output responses of the transistor correlated to the HER2 and CA15-3 concentrations, detection limits, and sensing sensitivity were determined.

Post reply on HN