[legitster]

Mesothelioma is not a "real" cancer in the traditional sense.

Your body has no way to expel fine asbestos fibers, and so they collect in your lungs and shred up the insides. When your body tries to respond by healing, it instead forms growths that constantly re-cut and heal themselves. So it's a type of cancer, but it's unique in that it's not based on malformed DNA.

So the idea that just being in the presence of asbestos is enough to form self-propagating cancers like it's some sort of radioactive isotope... doesn't make any sense. Asbestos on it's own is completely inert.

It's an improbably claim that requires extraordinary evidence.

[robbiep]

You’ve made a logical error here - you can basically say the same about every cancer.

The specific cancers that fit directly into the category you are carving out for mesothelioma are squamous and adénocarcinomas of the oesophagus, gastric mucosa and large bowel; lung cancers and other cancers of the epithelium.

The basic pathological process underlying cancer is cell dysplasia (usually caused by irritation/prolonged inflammation) which leads to metaplasia. Whether this is driven by a de novo mutation in that cell or from an external source is totally irrelevant and mesothelioma is certainly not unique in how it comes to fuck you up

[riahi]

Talc is used medically as a treatment for recurrent pleural effusions. It is introduced into the pleural space and triggers an intensely inflammatory reaction which more or less fuses the pleura together to prevent the accumulation of fluid (pleurodesis).

When a patient who has had a pleurodesis gets an FDG PETCT, they will have intense accumulation of radiotracer for years. It is very inflammatory. Even more so than asbestos.

I wouldn’t want talc anywhere inside my reproductive tract or anywhere inside my body if I could avoid it.

If you buy the chronic inflammation leads to cancer hypothesis, talc leading to cancer is not so far fetched.

[refurb]

> It is very inflammatory.

Location matters. The immune system reacts differently to foreign bodies depending on what tissue is in contact with it.

Damn near anything you add to the plural space is going to send your immune system into overdrive - the cells that line the plural cavity (mesothelial cells) are programmed to respond a certain way to their environment.

Contrast that with the cell that line your respiratory tract. There are cells that produce mucus, cells with cilia that sweep the mucus away from the lungs. They don't respond with a massive inflammatory reaction to foreign substances like the plural space does (at least not in a healthy human - asthma patients are different).

Same with the reproductive tract, especially the female one. We can insert IUDs into the uterine cavity without a massive inflammatory response.

[riahi]

The peritoneal cavity and the pleural cavity have very similar linings.

Talc introduced into the peritoneum is similarly inflammatory and has been known since at least 1943:

https://jamanetwork.com/journals/jama/article-abstract/26104...

Work has been done to demonstrate that talc can migrate from external perineal application into the female reproductive tract.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779257/

[refurb]

Your last paper is particularly interesting! Not only the results, but also the disclaimer!

"The authors declare the following competing financial interest(s): J.J.G., W.R.W., and D.W.C. have served as consultants and provided expert testimony in talc and other environmental litigation."

Ok, well good to set the context here.

But lets look at the results of the controls (no talc exposure) where the conclusions are remarkably cryptic, but I think we can figure it out!

The paper looked at tissue samples from ovarian cancer patients - a group of six who reported decades of talc use on their bottom and six who said they didn't use talc.

They used two techniques - polarizing light microscopy (very simple technique to look for polarizing molecules like talc) and then SEM/EDX which uses an electron beam and then measures x-rays emitted to identify exactly what the particles are.

"Polarizing light microscopy, as shown in the table, revealed a range of two to 17 birefringent particles per slide; these values are comparable to the lower end of the polarizing light microscopy results of the exposed patient"

Conclusion: using the same initial technique, we actually see the same particles (suspected talc) in the controls, but "at the lower end of the range for exposed patients". Very vague, but we can conclude they saw suspected talc in the unexposed patients but on the lower end of the range for the exposed. But that means the two groups overlapped in suspected talc particles.

Well, we better confirm those results with another analytical technique to confirm it's talc, right?

"Correlative SEM/EDX of the control tissue blocks showed a total of four talc particles across all patients: two in patient 2 (right ovary) and two in patient 3 (right fallopian tube). Of note, in Supplementary Table 1, both these patients had pelvic surgery more than 30 years prior to their ovarian cancer surgical procedure."

Oh crap! Those are talc particles in the tissue in the people not exposed to talc. Where did it come from? Oh, but it's probably the surgery they underwent prior!

Which on the surface makes sense - gloves, instruments, gauze, needles might have talc particles on them. Hell, all these tissue samples were removed and then handles by a lab as well - a ton of more exposure to talc is possible! In both the test and control subjects.

But anyways, yeah, it was introduced during surgery, that explains why we see talc in the non-exposed controls. But wait!

"Among the five patients in the main study, two had a history of tubal ligation"

Oh man! The patients that did use talc had surgery too! But the article doesn't call out the contradiction - if the reason for the talc in the controls is surgery, and your test subjects also had surgery, then you should find talc too! They just call out the surgery in an attempt to claim that with a tubal ligation, talc should be blocked from moving up the fallopian tubes. They don't even realize they contradicted their own results.

Jesus Christ this is a terrible, terrible paper. Written up and published for the sole purpose of trial lawyers - the authors had made plenty of money testifying to that fact.

Then on top, they do a bunch of hand wavy stuff to explain away the talc in the samples of the non-exposed, but don't realize at the same time they are explaining away the results in the people exposed too.

Pure garbage.

[riahi]

> They just call out the surgery in an attempt to claim that with a tubal ligation, talc should be blocked from moving up the fallopian tubes. They don't even realize they contradicted their own results.

They did address this and noted that in patients with tubal ligation the talc distribution was different and lymphatic rather than “mechanical” through the fallopian tubes.

Still not sure what your angle is here.

It’s known that talc is inflammatory. It’s literally used with that intention medically. We don’t use powdered latex gloves in the modern day nearly as frequently as before, mostly because of latex allergy but also due to concerns that talc exposure leads to worse peritoneal scarring/adhesions.

The fact that talc is present inside the surgical specimens is bad in and of itself, regardless of how it got there. That implies an environmental cause for the malignancy, a la asbestos or smoking.

[refurb]

I’m not sure you understood my reply at all.

[wolverine876]

> the idea that just being in the presence of asbestos is enough to form self-propagating cancers like it's some sort of radioactive isotope... doesn't make any sense.

It doesn't make sense to you and therefore is worth exploring. At the same time, unless one is an expert then the fact that they don't understand isn't much evidence that it's untrue.

Most people don't understand much about my field of expertise; their lack of knowledge doesn't invalidate most of my field.

[jb1991]

You forget this is HN where the majority think they can offer expert commentary on nearly any topic. It’s the peak of mansplaining.

[inglor_cz]

My old friend with no history of asbestos exposure, a sysadmin no less, died of mesothelioma last year. I only learnt that yesterday. (We grew apart...)

I spent an hour reading about that cancer. It seems that mesotheliomas without previous known asbestos exposure do occur.

[MichaelZuo]

Maybe he worked with fiberglass? I've heard a lot of things are similar to asbestos, they just need a higher exposure to do the same damage.

[refurb]

> So it's a type of cancer, but it's unique in that it's not based on malformed DNA.

This is absolutely incorrect.

Several genes are commonly mutated in mesothelioma, and may be prognostic factors. These include primarily BAP1, NF2, and TP53;[63] epidermal growth factor receptor (EGFR) and C-Met, receptor tyrosine kinases can also be altered and overexpressed in many mesotheliomas.

https://en.wikipedia.org/wiki/Mesothelioma#Pathophysiology