Saleh, I think the cancer stem cell theory is next to the mutation theory - which only had been proven for some 5% of cancers, although it was first proposed some 85 years ago, the next overestimated hype.

It is quite a huge difference if we have investigations studying tumor tissue samples from advanced cancers or if we look in detail about different sequences of carcinogenesis. Saying so, this goes in line with a huge difference in regard to metastasis (cancer progress) or initiation of carcinogenesis. 

The following paper's may be of value for you.

best

björn

Besides: I do not care at all, if someone who's home language is not English, uses a google translator.

Article Epistemology of the origin of cancer: A new paradigm

Article Cell-Cell Communication in the Tumor Microenvironment, Carci...

Hello

For translation are based on scientific references, I've edited to become clearer. I want to discuss the difference between these two models and how can advantage of them in the treatment .

Regards

the attached paper  may be of valuable in this issue

Hi Saleh.

My personal opinion is that cancer initiation and metastasis is not an orderly process that can be explained using knowledge gained from normal cell processes.

Many researchers are trained in analyzing normal pathways that cells can go through and they impart this to cancer cell biology.

But what if transformed cells do not follow established pathways?

A case in point is the epithelial to mesenchymal cell transition (EMT).

In this model, epithelial cells become mesenchymal in order to migrate. Then they revert back to epithelial cells after they colonize an organ?

To me, this does not make sense.

Can anybody explain this to me?

Saleh, I think the cancer stem cell theory is next to the mutation theory - which only had been proven for some 5% of cancers, although it was first proposed some 85 years ago, the next overestimated hype.

It is quite a huge difference if we have investigations studying tumor tissue samples from advanced cancers or if we look in detail about different sequences of carcinogenesis. Saying so, this goes in line with a huge difference in regard to metastasis (cancer progress) or initiation of carcinogenesis. 

The following paper's may be of value for you.

best

björn

Besides: I do not care at all, if someone who's home language is not English, uses a google translator.

Article Epistemology of the origin of cancer: A new paradigm

Article Cell-Cell Communication in the Tumor Microenvironment, Carci...

Hi Björn, can you provide full text of your papers?

Dear Steingrimur,

thanks, I added them and hoped it works, sorry if it didnt work out.

the critical thinking in regard of the communication of the stem cell theory with the mutation theory is on page 8 of the paper "Epistemology of the origin of cancer"

please find below the weblinks or if this even does not work, please be so kind providing your email and I will send them to you, mine is [email protected],

thanks

best

björn

http://www.biomedcentral.com/1471-2407/14/331

http://www.karger.com/Article/FullText/362978

http://www.biomedcentral.com/1471-2407/14/186

Hello

Thank to all answers , and all comments are welcome

Epithelial-mesenchymal transition (EMT) is a physiological process in which epithelial cells acquire the motile and invasive characteristics of mesenchymal cells. Although EMT in embryonic development is a coordinated, organized process involving interaction between many different cells and tissue types, aspects of the EMT program can be inappropriately activated in response to microenvironmental alterations and aberrant stimuli, and this can contribute to disease conditions including tissue fibrosis and cancer progression.. Accordingly, differentiating between how the EMT program differs between normal development and disease has become an important area of investigation . we need to future studies to address these questions using lineage-tracing approaches and new methods of in vivo imaging..

Regards

Hi Saleh, do you know of any specific marker that can distinguish mesenchymal cells from epithelial cells?

I have seen papers describing  vimentin as an EMT marker, but vimentin is expressed in most cells. I have seen papers describing loss of cytokeratin, E-cadherin, etc. staining as an EMT marker. Negative markers are not useful.

Also, it would help this discussion if you didn't copy/paste abstracts without acknowledging where they are from.

http://cshperspectives.cshlp.org/content/4/2/a011908.full

I have some work on EMT

http://www.cell.com/biophysj/abstract/S0006-3495%2813%2900794-7

http://stke.sciencemag.org/content/7/345/ra91.abstract

We use E-cadherin for epithelial marker, and Vimentin/N-cadherin for mesenchymal markers. The microenvironment can affect the cell fate on E or M (or possibly the hybrid intermediate phenotype), which may explain EMT and MET at different stages of metastasis.

The CSC theory is evolving. Originally CSCs are regarded as parallel to status of stem cells in the developmental tree, that is, unidirectional transformation from CSC to non-SCS. Nowadays more and more reports on conversion from non-CSC to CSC. Also there are debates on how we identify CSCs, and whether some "stem cell markers" are sufficient.

In the following paper, we observed interconversion between cancer-stem-like cells and non-cancer-stem-cells through chromosome missegregation--one can view it a "reprogramming" process happened in nature by overexpressing some genes (a whole chromosome 7 in this case),

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080898

Similar phenomenon has been reported in yeast

Hi Jianhua, are there positive markers for the EMT? 

A major problem with cell surface biomarkers for CSCs is that the selected cells may contain amongst the "phenotype" a few CSCs, but the vast majority are not CSCs. Hence study of such cells can be very misleading. Breast cancer CSCs are a good example. Using CD24neg, CD44pos, and CD326(ESA)pos markers, selects 1-2% of the tumor cells. However, limiting dilution assays in NOD/SCID mice yield 60-62.5% of animals with tumors in the "humanized" breast fat pad with "only" 100 of these cells (Filmore & Kuperwasser; Lange et al. (see below)). Remembering the Hewitt & Wilson measurement of the first in vivo radiation survival curve (using a transplantable leukemia for which a single cell sufficed for transmission), when injecting a cell suspension, the number of cells actually injected follows a Poisson distribution, so for an average of one cell per injection volume, 37% will have no cell and 63% will have one or more and hence get the tumor. Thus, the 60-62.5% induction rate for 100 cells means that only 1 of these cells (1%) was in fact a CSC. 1% of 2% yields a CSC fraction of 2x10^-4, in excellent agreement with our functional definition based hybrid spheroid assay result, without use of biomarkers, of 4x10^-4. Thus, the biomarker combination eliminated 98-99% of non-CSC cells, but the selected population (1-2%) was still 99% non-CSC. (This was all shown in: In measuring the radiosensitivity of breast cancer stem cells (CSCs), cell surface biomarkers purporting to designate a CSC “phenotype” are an insufficient definition of CSCs, since > 98% are not CSCs. Christopher S. Lange, et al., Radiat. Res. 58th Annual Meeting Program Book: pg 126-127, Abstract PS5-48, September 30 – October 3, 2012, San Juan, PR.). Ignoring the quantitation has led to several papers (Hill; Kearns & Shibata) pointing out that the numbers in such biomarker experiments have been internally contradictory, calling into question the validity of a CSC model based on such data. The CSC model is useful when properly applied.

An excellent post Dr. Lange. I took the liberty of re-posting this on the Theodor-Billroth Academy Group on Linkedin with the post attributed to you and a link to this post by you.

Hi Steingrimur,

You got the point about EMT markers.

For our experiences, EMT markers are really depended on the cell lines that you chose for your experiments. But in general, the contrary trends of expression levels of E-cadherin and N-cadherin/Vimentin could be used as the markers. In details: before EMT, you will see E-cadherin protein expression but no or rare N-cadherin/Vimentin, After EMT, you will see the vanish of E-cadherin but the cumulation of N-cad/Vimentin. PS: Depending on cell lines, some papers also use Snail or Twist as EMT markers. 

Hi Jingyu, thank you for your response.

But in terms of CTCs isolated from cancer patients, are there any positive markers that can be used to identify epithelial cells that have turned to mesenchymal cells?

To me, aspects of the EMT hypothesis does not make sense.

For this, epithelial cells acquire mesenchymal cell traits, migrate and revert back to epithelial cells once they colonize an organ.

Can you understand my reservations?

Hello Steingrimur Stefansson and all researchers

For the Progressive Stages of EMT

1-Epithelial Layers

Epithelial cells compose highly organized layers that make up functionally diverse sheets, tubes,and vesicles. Individual cells display apical-basal polarity and are closely adjoined by tightjunctions , adherens junctions , and desmosomes . Adherens junctions areanchored to the cytoskeleton by b-Catenin .

Key Molecules (EMT Effectors): EGF, FGF acidic, HGF, PDGF, TGF-b, Wnt-3a

2-Loss of Tight Junctions:

One of the earliest events during EMT involves disassembly of the lateral intercellular seals close to the apical surface. This triggers redistribution of key molecules, disruption of the polarity complex, and cytoskeletal reorganization.

Key Molecules: Actin, Claudins, JAM, Occludin, p120, Par3, Par6, Zona Occludens

3-Loss of Adherens Junctions & Desmosomes:

Adherens junctions composed of E-Cadherin, and desmosomes made up of a desmoglein and a desmocollin are dismantled. The molecules that anchor these specialized cell-cell contacts to the cytoskeleton are redistributed.

Key Molecules: a-Actinin, a-Catenin, b-Catenin, E-Cadherin, Desmocollins, Desmogleins,Plakoglobin, Plakophilin, Vinculin

4-Cytoskeletal Changes:

Following loss of junctional complexes and downregulation of E-Cadherin, b-Catenin is no longer sequestered in the cytoplasm and translocates to the nucleus to activate b-Catenin responsive genes. The actin cytoskeleton forms stress fibers that anchor to focal adhesion complexes and promote cell migration.

Key Molecules: Actin, Cytokeratins, S100A4, a-Smooth Muscle Actin, Vimentin

5-Transcriptional Shift :

Snail, ZEB, and bHLH family transcription factors suppress epithelial markers and activate mesenchymal genes. The cytoskeletal protein vimentin is upregulated , as is the deposition of the extracellular matrix (ECM) protein Fibronectin .

Key Molecules: Ets-1, FOXC2, Goosecoid, LEF-1, Snail 1, Snail 2 (Slug), Twist-1, ZEB1, ZEB2.

6-Increased Motility & Migration :

ECM components stimulate integrin signaling and promote the formation of focal adhesion complexes. Upregulation of N-Cadherin increases cell motility. Metalloproteinases degrade the extracellular matrix and facilitate cell migration.

Key Molecules: N-Cadherin, FAK, Fibronectin, a5b6 Integrin, Laminin-5, SPARC, Syndecan-1,Vitronectin .

also , Many studies of EMT marker have supported the importance of TGF-b signaling for the repression of epithelial genes and induction of mesenchymal genes in vitro and in vivo. Activation of the TGF-b signaling pathway requires a heteromeric receptor complex composed of two type I and two type II transmembrane serine-threonine kinase receptors. Following binding of TGF-b,type II receptors phosphorylate type I receptors, which in turn phosphorylate Smad2 and Smad3. Smad2/3 forms a trimer with Smad4 which translocates to the nucleus and interacts with transcription factors, co-activators,and co-repressors. In addition, cross-talk between TGF-b and PDGF , Wnt, and Notch signaling pathways has been shown to contribute to EMT.

Reference in attachment

Regards

Hi Steingrimur,

Here is my thought. It might be difficult to use markers to directly demonstrate that CTCs come from epithelial cancer cells in the primary tumor. One may find the connection from the genomes (correlation of mutation patterns).  

Daniel Haber has studies on CTC gene expressions.

to @Dr.Markus Schaefer, the new views had been provided, please find it here for your convinience again:

http://www.biomedcentral.com/1471-2407/14/331

http://www.karger.com/Article/FullText/362978

http://www.biomedcentral.com/1471-2407/14/186

Hi Jianhua, can you elaborate?

CTCs captured by the CellSearch system has been shown to be a clinically valid assay. This assays uses EpCAM to capture CTCs and  uses anti cytokeratin 8, 18 and 19 to identify epithelial cells.

Hi Saleh, for the EMT story, some proteins are either upregulated, downregulated or redistributed to account for how epithelial cells can be migratory.

Bottom line is that I have not seen evidence showing that cancerous epithelial cells revert to embryonic mesenchymal cell behavior to migrate as CTCs and then revert back to epithelial cells when they invade an organ.

Then they do the whole thing over again to form secondary, tertiary, etc. tumor sites.

To me, this does not make sense.

CTCs are not smart bombs.

Dear Dr. Alkarim,

The key challenge for the cancer stem cell theory is that it still urgently needs an explanation about how cancer stem cells evolve into cancer by somatic cell evolution. As the non-stem cells can become cancer stem cells, the power of the cancer stem cell theory is drastically reducing. We have discussed this issue back in 2007 (see: Cancer genome sequencing: the challenge ahead, BioEssays).

To unify different theories in cancer research, the key is to apply the evolutionary concept. The following papers might be helpful. By understanding genome mediated cancer evolution, it is easier to understand the involvement of some cells with stem cell markers.

Chromosomal instability (CIN): what it is and why it is crucial to cancer evolution

http://www.ncbi.nlm.nih.gov/pubmed/23605440

Evolutionary mechanisms and diversity in cancer.

http://www.ncbi.nlm.nih.gov/pubmed/21925306

Cancer genome sequencing: the challenges ahead.

http://www.ncbi.nlm.nih.gov/pubmed/17621658

http://www.ncbi.nlm.nih.gov/pubmed/23605440

http://www.ncbi.nlm.nih.gov/pubmed/21925306

http://www.ncbi.nlm.nih.gov/pubmed/17621658

some references that maybe helpful to you:

Shackleton M, Quintana E, Fearon ER, Morrison SJ. Heterogeneity in cancer:

cancer stem cells versus clonal evolution. Cell. 2009 Sep 4;138(5):822-9.

Kreso A, Dick JE. Evolution of the cancer stem cell model. Cell Stem Cell.

2014 Mar 6;14(3):275-91.

Magee JA, Piskounova E, Morrison SJ. Cancer stem cells: impact, heterogeneity,

and uncertainty. Cancer Cell. 2012 Mar 20;21(3):283-96.

Dear Alkarim;

If we reduce the carcinogenesis to two theories , it is very great succes for us. We are still in the beginning of the beginning.

Dear Dr. Luchnik,

The importance of CIN (chromosome instability, or better yet, use genome instability) for cancer evolution is that the altered genome defined macro-cellular evolution is the key process. Large numbers of molecular mechanisms, including wound healing and inflammation, contributes to cancer evolution through the link to CIN.

That is the rationale we have established: the evolutionary mechanism of cancer, which can explain many specific molecular mechanisms.

More info please see our web page:

http://genetics.wayne.edu/edunew/faculty/heng/lab/Home.html

Let me answer in two blocks, at first pointing out the reality what we know or better what we do not know about genetics and especially, why there is a misleading in criticial thinking:

Block A:

Is a disease reflected by polymorphisms or chromosomal instability?

It rather seems, that correct observation(s) are transated and transformed into a wrong conclusion.

An apple found in a car is not synonym of prove, apples grow in cars.

Further I allow myself reminding about the following:

-the known number of SNP’s is 62,676,337 (23 Jul 2013)

-humans have 23 paired chromosomes (46) and (so far known) 21,000 haploid coding genes.

-the number of base pairs are appr. 3.3 x 109.

-chromosome 1 alone has 249,250,621 base pairs even 4,401,091 variations.

-the mutation rates in eukaryotes are 10-6 to 10-10.

-the umber of pseudogenes is: 13,000

-further humans have large numbers of mobile genetic DNA:

--for example Alu (alone) has 50,000 active copies

--appr.more than 40% of the total genome

-additionally humans have large numbers (also poorly understood) of mitochondrial genome

-and non-coding DNA is about 98% of the total human genome (!)

If someone would state, that in the long-term future, there is hope, that maybe big data will help us increasingly to understand genetic information and its role within diseases, I would of course agree.

I do not doubt, and there is o course enough prove, that genetic changes can be measured and observed in advanced cancers.

This observation is not synonym of prove, such would be the cause triggrering carcinogenesis, the development of disease. 

Further someone may please – independent from our papers - read in detail the following in regard to the somatic mutations in the blood genome, which occur routinely:

Broske et al. 2009, Catlin et al. 2011 and Welch et al. 2012 with its result:

“Note, however, that comparison of mutation rates for any clone/genome is subject to uncertainty because one cannot determine when each mutation was acquired and how the analyzed clones expanded during a lifetime. Also, inconsistencies between sequencing techniques and downstream analyses complicate an accurate comparison of mutation numbers”.

Block B:

If someone wants explaining the somatic mutation theory by irradiation than critical thinking is needed as well for understanding the different cancer incidence curves with its different dose-response curves in Hiroshima and Nagasaki after the A-bombs:

Hiroshima: a straight curve line as the ionizing radiation dropped and the high linear transfer (LET) caused double strand breaks, and the repair enzymes had no template to use as a guidepost to repair the damaged DNA.

Nagasaki: the low LET radiation caused single strand DNA damage and the repair enzymes were able to use the intact template to repair the DNA damage- as a consequence, the dose-response curve for cancer was S-shaped (as it is true for most chemicals and pharmaceuticals).

The 1-hit, nor the 2-hit or multiple hit theories do not account for repair enzymes or even not for epigenetic modifications protecting against the development of the vast majority of cancers.