Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Airthumbs on 10/01/2011 07:31:02
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After posting a comment on another thread I would like to know if any one has any idea as to whether or not having cancer causes your body to smell differently. I would be looking specifically at a change in 1 part per trillion or less.
Everywhere I look on the internet I see stories of people saying they can smell cancer, from funeral directors to nurses. the reason I ask this question is that a device has been invented that can detect smells one part in a trillion. Dogs can supposedly smell prostate cancer in urine and they can smell substances one part in a million.
I would like an answer as I feel this new device could be a tool for detecting cancer and other medical problems.
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Cancer "smelling" was presented on a recent TV show, "The Big C" in which a neighbor's dog could apparently able to smell Cancer. But, that is Hollywood too.
There was a recent discussion about smelling chips that could at least pick up some substances at very small concentrations. I didn't look at it closely enough to see how broad of a spectrum they were picking up.
I suppose the problem is defining exactly what you are smelling.
You already have various tools.
IR, NMR, PCR, etc... that can analyse various fluids & secretions for molecules or DNA. But, to a large extent they only would work with something that is well defined. I assume you could add sweat to the list of fluids to analyse.
An interesting would be to look for changes in a person's "smell" over time, not attributable to soaps & perfumes.
Maybe take 1000 smokers... and get a good whiff of their breath as a baseline, then test it repeatedly over the course of a decade. Smoke, of course, would confound the study, especially if they chose to quit (which you could not ethically discourage). Perhaps you could study ex-smokers who had previously smoked for an extended period.
You could also study other aspects of lung health such as pneumonia with a breath test.
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Hmmm. Well my concern would be how advanced the cancer would have to be before it became obvious by smell, to machine, dog or whatever.
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I don't know if this is ethical? I would follow a sample of hospitals with existing screening techniques and identify which patients have early stages of all known types of cancer.
Monitor each patient for a fixed period and try to identify a common factor in the chemical changes of the patients smell comparing them patients without cancer. Each time take samples using an electronic nose. Doing these tests in a completely sterile environment would hopefully eliminate a large piece of noise in the background data.
Well anyway, that would render the job of a large computer and some search algorithms, who knows maybe some interesting modelling could be achieved?
To simplify the test maybe first run the same experiment on patients with known problems that produce a noticeable smell. Using the information, from data collected, electronic noses could be programmed to recognise air borne compounds/molecules caused by illness.
[;D]
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If there was a machine that could pick up this smell, whatever it is, then I would be inclined to start with patients who have confirmed cancer, of different types and see if there is a correlation with what the machine picks up and the type of cancer.
Further to that if it showed no correlation between type of cancer and smell, I would analyse biopsies of the cancer in the patients the machine had identified, to see if there was a particular mutation unique to these cancers.
Just my tuppenceworth [:)]
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The problem I think is that first you need to identify the cancer smell if even one exists and programme the machine to detect that smell. Maybe I am mistaken.
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The problem I think is that first you need to identify the cancer smell if even one exists and programme the machine to detect that smell. Maybe I am mistaken.
I thought there was mention of a machine that already did that??
Might be my mistake, I think I read above posts wrong!
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Check this link out, I must have caught this subconsciously from somewhere. Or I just re invented something that was invented last year!
http://www.newscientist.com/article/dn3702-electronic-nose-sniffs-out-lung-cancer.html
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Check this link out, I must have caught this subconsciously from somewhere. Or I just re invented something that was invented last year!
http://www.newscientist.com/article/dn3702-electronic-nose-sniffs-out-lung-cancer.html
That is 7 years old... I wonder why it hasn't made waves yet. I assume the "E-Noses" are more accurate now.
Lung Cancer seems like a reasonable starting place since you get air movement so close to the cancer cells. There are likely differences between cancer types, small cell, large cell, etc. That likely increase the specificity of the device, but also make it more complicated.
For skin & urine/BM specimen smells... I presume there would be an entirely different set of rules. I.E. Each core cancer type would likely have different properties and odours.
I'm envisioning a result somewhat like an IR spectrum or Gas Chromatograph. I was thinking of using the existing devices, but I see the likely problem with PPB or PPT detection. It would likely give a much more discrete output, with varying outputs from 20 or so sensors.
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One of my dogs, was increasingly obsessed by my uncles feet when he was dieing from (a particualrly unpleasantly aggressive) cancer. It turned out that there was some form of secondary tumour in his left foot. This is of course purest annecdote and in no way a scientific observation, it may have a perfectly simple explanantion such as my uncle struggled to clean his feet...
It just seemed a little bit too much of a coincidence.
As an aside, as far as I know the mechanisms wherby smells are detected/ identified biologicaly is not fully understood.
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I think you could safely now say that if an electronic nose can detect cancer because of it's smell then it is possible a dog can too. Some of these cancerous smells are caused by:
[8]trimethylamine
[8]di-trimethylamine
[8]aliphatic acids
[8]alkanes
[8]benzene derivatives
As for compounds emitted directly from the site of the cancer, I don't know if anyone has used the electronic nose yet to try? Maybe dogs really are a man's best friend.......
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One of my dogs, was increasingly obsessed by my uncles feet when he was dieing from (a particualrly unpleasantly aggressive) cancer. It turned out that there was some form of secondary tumour in his left foot. This is of course purest annecdote and in no way a scientific observation, it may have a perfectly simple explanantion such as my uncle struggled to clean his feet...
It just seemed a little bit too much of a coincidence.
As an aside, as far as I know the mechanisms wherby smells are detected/ identified biologicaly is not fully understood.
Like your dog....
My mothers dog for months before she was diagnosed kept digging at her chest and stomach area.. when she stopped him he would lie across her lung area and forcefully try to stop her from moving her off the area by pushing hard against my hands or hers.. The doctor saw her tummy when examining her as she came in cause she got sick like a bad cold that wouldn't go.. they thought it was pneumonia but it was lung Cancer.. when it metastasized the dog spent hours trying to position herself in a couple different places against her spine and lung and chest area.. as if she were taking shifts on each spot.. he would sniff her and lick those areas constantly even through her gown... It was weird but my dog comes to me in much the same way when I have trouble and pain.. and he acts as if he is applying body heat to cold areas and he pin points the area where I am cold.. looks sniffs examines feels and then positions himself and stays there until I get up or move him.. some times he refuses to move the lazy boy! Seriously I think they do smell infection, cancer sickness what have you but thats just my humble opinion... I hope this machine sniffer works. can you imagine the ramifications of that especially if it could detect it in early stages... Like when you recognize your child's sick breath a day or so before they get sick... Its amazing...
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I would love to learn more about this if you find out more.. Thanks.
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Just looking up if dogs could smell or sense infection and if it was documented to heal and stumbled across this. Its really crazy but my dog was attracted to a wound i had a problem with on my leg that had gotten infected. I tried antibiotics even IV and couldnt get it to completely heal. I would wake up and he would be licking it. The crazy thing was not a couple days of him sniffing it out and licking it it healed! I looked up other things on this and most are documented as its not good to do ? Who knows just thought id let you know as you said you were interested in learning more... :)