Blood tests for cancer and Alzheimer's Disease

As a cancer survivor with a strong family history of cancer, I have been following the development progress of blood tests for cancer for years. Until recently, the only blood test available for breast cancer was CA-125, which is only useful for detecting recurrence and even then isn’t really very accurate.

There have been no physical tests for early Alzheimer’s Disease (AD) or Parkinson’s Disease (PD). Recently, a test for PD was announced – detection of alpha-synuclein in spinal fluid. That’s better than nothing but far more invasive than a blood test.

New Blood Tests Offer Possible Early Detection of Cancer and Alzheimer’s

Questions include who should be getting them, and what patients should do about positive results

By Laura Landro, The Wall Street Journal, April 19, 2023

Using a single blood sample, one test released last year can detect early signals for more than 50 types of cancer, including some such as pancreatic cancer for which no routine preventive screening assays have existed up to this point. Other blood tests are proving accurate in detecting amyloid plaques—the proteins that clump together in the brains of Alzheimer’s patients, leading to eventual loss of memory and thinking skills—even before cognitive declines have been experienced…

Grail Inc., a Menlo Park, Calif., biotech company, has produced a $949 cancer test called Galleri, intended for patients at higher risk for cancer, including those over the age of 50 or those with other risks such as smoking, obesity or a family history of cancer. It uses DNA sequencing and machine-learning technology to analyze DNA shed by cancer cells in the bloodstream.

In addition to determining whether a cancer signal is present, Galleri includes predictions of where the signal most likely is coming from in the body. Although it detects a positive signal in only 1.1% of tests, about 4 in 10 patients with a positive cancer-signal result are expected to have a confirmed cancer diagnosis, according to study data. There are caveats: If no cancer is confirmed with further testing, it could mean the test was insufficient to detect it, including cancer that is not shedding DNA into the bloodstream. And false positive and false negative results do occur, as in most cancer testing…

The new Alzheimer’s blood tests, meanwhile, are meant to help determine if memory loss and brain aging are due to early stages of the disease. These tests, available with a doctor’s prescription, include one from lab giant Quest Diagnostics Inc. and one developed at Washington University School of Medicine in St. Louis and licensed to C2N Diagnostics… At $500 to $1,250, blood tests for Alzheimer’s disease aren’t covered by most health insurance… [end quote]

Since obesity is a risk factor for both cancer and Alzheimer’s Disease the potential customer pool for these tests is immense.

Detecting cancer early can be life-saving. Detecting AD early can potentially qualify a patient for one of the clinical trials of drugs to slow the progress of the disease.

Since insurance doesn’t reimburse for these tests they will be used primarily by those who can afford them. For example, any senior citizen who has a family history of cancer, such as my older brother, @OrmontUS.

If the tests get approved for reimbursement by Medicare they would have Macroeconomic significance since the cost would run into the billions of dollars.



Keeping hope alive is a huge issue, while I’ve not had any issues, sister, MIL dealt with breast cancer, but back in the late '60s, where much less was known, much later, my brother fell into the multiple myeloma slide, held on a long time, but likely ignored early symptoms. Couple years back our daughter chase a tremor to a glioblastoma diagnosis, treatment, which did hold well for a time, but when a 2nd site, operable, appeared, the pause to allow that to heal, turned loose the original, and while hope was there, it soon faded, even with the best specialists, etc…

So many variations, melanomas have taken friends, neighbors, many, many variables, it has to be a rough world for those doctors to deal with daily… Early screening, jumping on to ASAP, helps everyone, research continues…

So we keep an eye on the science as well… Hope it, what they learn, helps others…


Well, I strongly suspect that if the blood tests that show increased risk of diseases that commonly manifest themselves in the older age group, mainly the 4 Horsemen…heart disease/ASCVD, cancer, Alzheimer’s and so-called “foundational diseases” associated with metabolic syndrome … are limited to these “older age groups” they’re likely to have relatively little positive effect on treatment outcomes (assuming any effective treatments are available). Most (all?) are diseases that develop over a long period…as in decades, not years, from that early departure from healthy homeostasis.

A bit, say, like doing CAC scan and CT angiograms in a 70 year old.


In some cases you are right. In others, you are wrong.

An MRI found my bilateral breast cancers when they were 5 mm (1/5"), Stage 1.

Beware of making blanket statements.


Early detection of a lesion…but not the first sign of departure from healthy homeostasis/start of the disease process. Wasn’t an inaccurate blanket statement.


It is more environment than DNA. Who knows what the actual percentages are in the granular breakout are. VeeEnn is correct in simply saying the longer term effects of personal care matter greatly to disease creation.

It is something you believe from all I have read.

That does not mean you did anything ‘wrong’ to get a breast cancer lesion. But I am not aware medically of the life style issues that aided the occurrence. It is not a moral issue.

Changing behaviors to cope with environmental challenges has some stress involved. Those stresses are taken by individuals as moral bad v good behaviors. Not the reality of it.

Actually, I wasn’t saying that at.

The consequences of poor lifestyle choices has so taken over the narrative surrounding health and disease that it’s easy to forget…or to be unaware of in thefirst place…that good custodians of their bodies can also be affected by diseases that come at them out of left field. Oftentimes diseases that appear to share the same characteristics of self inflicted disease … ASCVD and some cancers to name but two.

As small as the number might be, these (we) are the folk who stand to gain the most from “next generation” medical care…i.e. Identifying the genetic underpinnings of disease and applying interventions that target this before or at first sign of departure from healthy homeostasis. Literally at or before “the first cell” …mentioned in a different thread.


I could say that about my birth defect. Others might say that about a car accident.

Oddly enough those are not DNA they are both environmental.

It is not so simple that very good self care leaves causality purely to the DNA. There are unseen factors. Just going back to commercial branded soaps and other chemicals in the air, water and food there are unknows.

We were born into the best of times and those times may get even better but we came out of some terrible abuses as well.

I’m sure you/they could…but since, as you say, your birth defect and road traffic accidents aren’t a genetic issue, I won’t bother.

Howver, it would be a mistake to infer that I was suggesting that those of us who’ve been good custodians of our bodies are solely at the mercy of our genetic makeup but, compared to the chosen lifestyles of a good many, we’ve come pretty darn close (malarkey about “unseen environmental factors” notwithstanding)

As I pointed out, the “next generation” approach to unraveling the genetic underpinnings of the big killer diseases has the potential to open up novel interventional possibilities. Possibilities that effectively reduce genetic predisposition to almost zero. That obviously won’t eliminate these diseases entirely since there are folk dying of them who have been gifted with a low genetic risk in the first place but have smoked, boozed, eaten and sat their way to the disease phenotype … and will continue to do so.

The technology comes a bit late for the likes of me and Wendy but it’s quite an exciting prospect for future generations.

Even as I read this, I realise that this is really just a sophisticated, technologically advanced equivalent to being aware of family history. I realised my mistake in this regard with my first visit with the intervention cardiologist last year. I’d previously acknowledged my mum’s early onset of ASCVD but put it down to smoking, and, since I didn’t smoke, well…

It wasn’t until my man went through all my family in detail…I’m a singleton but my mum had 5 brothers and one sister who, it dawned on me, all died “suddenly” and the brothers all before age 60. I have no idea if emphasising this REALLY strong family history at primary care level would’ve raised the index of suspicion WRT my “mildly elevated” LDL-C. Somehow, I doubt it. I have this nagging feeling (right or wrong) that primary care docs …at least, those who’re young enough to have graduated medical school in the era of the obesity epidemic (which is pretty much most of them today)…are so overwhelmed with patients whose craptaculous lifestyle has produced the lipid profile that I share that my obvious good custodianship only served to create a false sense of security to the extent that I missed the window of opportunity to prevent the situation I’m in right now.

I saw the cardiologist a couple of weeks ago and articulated something along these lines (not in a way that made it look too much as if I was looking to “blame” anyone) He didn’t disagree with me.

While on the elliptical yesterday, I listened to a very interesting podcast with Peter Attia (interviewed by Steve Levitt) about this issue.

Adding Ten Healthy Years to Your Life

I do a lot of my Z2/MAF/ASCVD mitigation training on the treadmill listening to Peter Attia podcasts. I’m a subscriber to his site primarily for the cornucopia of guests he interviews…a good many on just these topics. A serious eye opener into research that’s set to be a game changer in the future…a good bit in the here and now, too.

@Leap1 I was aware of breast cancer in my family starting at age 2 when my mother brought me to visit my grandmother who was dying of breast cancer. (Yes, I have a memory of that visit.) My mother had a lifelong terror of breast cancer since her mother, grandmother, plus aunts and cousins all had this terrible disease.

As a result, I did everything possible to prevent and detect breast cancer. I did 2D mammograms annually until 3D became available so I switched. I exercised vigorously several times a week and had a low-carb diet starting in my 20s, even before that was known to reduce risk. When Vitamin D was shown to reduce risk I increased my Vitamin D intake.

When a 3D mammogram showed an anomaly (microcalcifications but not cancer) I immediately got an MRI and paid out of pocket. That showed bilateral tiny (5 mm) active cancers. I had a bilateral mastectomy.

Since the cancers were tiny and had not spread the cancer was Stage 1 and I did not need chemotherapy.

I agree with @VeeEnn that decades of healthy living helped delay and slow the growth of my cancers. But I disagree that this is enough. Early detection of cancer, using a blood test that can even detect cancers that have no detection technique to date (such as pancreatic) can save lives. Healthy living alone isn’t enough to prevent cancer. We are all surrounded by mutagens since our culture is permeated by synthetic chemicals.



Here’s a quote from the podcast I mentioned above -

“All of their genes when you look at them, are basically genes that are chronic disease prevention genes. So their superpower is delaying the onset of chronic disease, full stop. And therefore that’s basically the insight that drives all of medicine 3.0. You have to live longer without disease, not stretch out the time you can live with a disease.”


This is the little “teaser” from Peter Attia that prompted me to take out a subscription…

I was particularly interested in the exercise physiology part. Initially I thought I’d be crafty and do a monthly subscription and cherry pick what was of interest to me and then cancel. The amount of stuff I ended up becoming interested in prompted me to change to annual subscription.

The interviews with researchers in cardiovascular physiology and disease plus lipidology in general is what made me start thinking that maybe the reassurances about my healthy lifestyle choices reducing the potential risk of my LDL-C levels (around the 120-130 mark…definitely “mildly elevated” in a general sense) might just, possibly, may perhaps be wrong. And so they were. VERY wrong.

You’re not disagreeing with me, Wendy…as I’ve said many times even the best custodians of their body can get stuck by stuff out of left field

You’re also missing the thrust of what I mean when talking about “next generation” detection/treatment. The tests in your link…assuming they live up to expectations…will be a wonderful addition to early detection. However, it’s still early detection of a disease once it’s started. A more sophisticated version of what we already have. Implications for the future … if/when it becomes possible to determine how to mitigate genetic predisposition…suggest that there may be interventions available before even this very early stage of a disease.

Here’s something that irks me, though … and I’m pretty sure that it’s more a feature of ASCVD than breast cancer… and it’s that there are so many folk around nowadays who are or have been pursuing “lifestyle issues that aid the occurrence” of a given disease with their foot firmly on the accelerator and driving towards premature morbidity/mortality that it’s apparently inconceivable that there are folk who don’t. That there are those of us around with our foot (clad in a lead boot) firmly on the brake pedal … but still unable to fully escape the genetic hand we’ve been dealt. As I mentioned upstream, I have a shrewd idea that my obvious pursuit of healthy living provided a smokescreen that delayed the appropriate timing of meaningful therapeutic interventions.

My daughter is not sleeping on the issue. She has an appointment with my primary care doc (the one who thought the CAC scan was a worthwhile aid to decision making…but subsequently confessed she expected a close to zero score) and a CAC scan on the radar screen. Had a heads-up this week as one of the vet techs who works for her and is the same age (41…gawd THAT makes me feel old) has just had a heart attack and two stents placed.


That is an impossible statement. Meaning you are not a stat but you are basing this assumption about yourself on stats.

Unfortunately whatever in the chemical bath we occupy that might kick off your DNA might be meaningless to most people’s health.

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Am I? I could’ve sworn I was basing it on the reality that I’ve consciously and conscientiously made the same healthy choices on dietary and exercise habits that Wendy describes upstream. Maintaining a lean bodyweight with favorable body composition, alongside avoiding smoking, over use of alcohol. Consistently. For a good half century. Longer if you count the time on my mum’s watch.

That is the point, your profile is full of things where statistically people live longer. The assumption is your disease happened anyway perhaps hereditary, DNA.

You well could be right for yourself. There is so little known though that you could well be wrong. The stats on healthy living longer are the blanket statement to an extent.

Yes you and I both need healthy living. That does not change.

But assuming a few things are hereditary not environmental the jury is still out. Solving problems with DNA treatments in patients might point to DNA but that could be very inaccurate. Treatment in that case is not prevention.

Indeed I could…but then I’d want to come up with some, as yet, undiscovered reason for my phenotype. Whilst we’re all subtly different as individuals, the difference isn’t so great that decades of evidence should be refuted because there’s apparently “so little known” in favour of some imaginary scenario without a plausible mechanism to refute what is known. I’ll settle for currently available evidence for now.

Here’s a brief review for anyone interested in a disease that every one of us likely has to some degree…

Clinical Implications of Lipid Genetics for Cardiovascular Disease - PMC.

I like background stuff like this because, although it doesn’t answer the Big Question…“Why Me?”, there’s a lot to answer “How?”. Stuff I didn’t know … along with what I know that just ain’t so.

** Of note: this is just a superficial glance (srsly!) at the lipidology of ASCVD…the familial hypercholesterolemias. The plumbing, as it were. Not the electricals (Afib anyone?) Nor the whole structure (cardiomyopathy)