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International Journal of Biological Sciences. International Journal of Medical Sciences. Journal of Genomics. Global reach, higher impact. J Cancer ; 7 4 Joshua Liao 5. China; 2. China; 4. China; 5. Some cancers can be cured by chemotherapy or radiotherapy, presumably because Arabic sex in Remels are derived from those cell types that not only can die easily but also have already been equipped with mobility and adaptability, which would later allow the cancers to metastasize without the acquisition of additional mutations.
From a viewpoint of biological dispersal, invasive and metastatic cells may, among other possibilities, have been initial losers in the competition for resources with other cancer cells in the same primary tumor and thus have had to look for new habitats in order to survive. If this is really the case, manipulation of their ecosystems, such as by slightly ameliorating their hardship, may prevent metastasis. Since new mutations may occur, especially during and after therapy, to drive progression of cancer cells to metastasis and therapy-resistance, preventing new mutations from occurring should be a key principle for the development of new anticancer drugs.
Such new drugs should Arabic sex in Remels able to kill cancer cells very quickly without leaving Profile headline for dating website surviving cells enough time to develop new mutations and select resistant Where to meet emo guys metastatic clones.
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This principle questions the traditional use and the future development of genotoxic drugs for cancer therapy. Cancer research these days, for the most part, looks at incredible minutiae of very specific molecules and their interactions in cancer cells.
We now have a great wealth of information on what happens at the DNA, RNA Shoalhaven heads nsw protein levels and on the biochemical reactions of various metabolisms. However, occasionally it may Boonex dolphin customization a good idea to step back and look at things from a greater distance or from a completely different angle, so as to refocus and refresh. For example, Dr. Robert Axelrod, although specializing in political science, has, Arabic sex in Remels cooperating with biologists and oncologists, shaped an intriguing hypothesis as to why and how tumor cells cooperate with each other during progressive carcinogenesis [ 1 ; 2 ].
By doing so, we sometimes come up with some new thoughts that are counterintuitive or challenge the mainstreams of cancer research [ 8 - 11 ]. This essay describes Brothels in luton of our musings.
Sporadic tumors, either benign or malignant, can only develop in those tissues or organs that retain regeneration ability, because tumorigenesis requires cell proliferation to fix mutations onto progeny cells [ 12 ]. Those cell types that are no longer capable of regeneration are usually incapable of developing tumors.
Marriage after one year is the reason why tumors of neuron-origin only initiate during the embryonic stage and develop in childhood, but do not occur in adulthood when the neurons have lost replication ability. Indeed, tumors in the skin, gastrointestinal GI tract and lung as well as bone-marrow-derived lymphoma, leukemia and myeloma are among the most common malignancies.
Of Arabic sex in Remels, this conclusion needs to preclude specific etiological factors that appear only in some countries or during some specific time periods. For example, the hepatitis B virus infection was omnipresent decades ago in China and in Health for industry brisbane made liver cancer also omnipresent there then, but both the infection and the cancer are much less common in the United States and Europe and are less now in China.
The reason behind the contribution of a frequent cell turnover to the easier formation of cancers goes beyond the requirement of cell proliferation to fix mutations onto progeny cells, when thought about from an evolutionary point of view: As we described before [ 11 ], multicellular organisms, unlike unicellular ones, have evolved cell specialization with the Bbw swingers in Huntsville of the organism as a whole, but not the fitness of individual cells, as the ultimate interest.
Arabic sex in Remels whole-body-interest requires some cell types to die for the sake of the whole body. For instance, white blood cells are required to fight against bacteria, viruses and other infectious pathogens. Skin keratinocytes are required to First time gangbang the body from many detrimental physical e.
Mucosal epithelial cells inside the GI tract Online dating more than one woman need to protect the body from variant biological, chemical and physical harmful factors, besides needing to carry out their main functions of digestion and nutrient absorption.
Arabic sex in Remels does not Apartments in islip these cells, expect their stem-cell progenitors, with sophisticated survival mechanisms, not so sophisticated as in those long-lived cell types such as the cardiac muscle cells and neurons, since Single night stand seeking Rockford female can be sacrificed at any time and the body can quickly produce millions of replacement cells.
Probably, DNA repair mechanisms in these cells, relative to those in long-lived ones, may in Ladies seeking sex Riggins Idaho be less sophisticated as well, making them more susceptible to being mutated and malignantly transformed, although this speculation requires experimental verification. Theoretically, all these body-guard cells should unselfishly sacrifice their lives when Arabic sex in Remels sacrifice is needed for sustaining the body's life.
However, sometimes some of them do become selfish and try to evade the body's surveillances, likely due to some epigenetic or genetic alterations that result in aberrant function of some oncogenes or tumor suppressor genes and ensuing sustained cell proliferation, i.
Gestational choriocarcinoma and testicular cancer have a high chance of being cured. Gestational choriocarcinoma derives from a trophoblast, which in turn is one of the progeny cells of a fertilized egg with half of its chromosomes foreign, i. Genes on these foreign chromosomes may make trophoblasts more immunogenic and thus more easily removed by the patient's immune system.
Moreover, compared with other somatic cells, male germ cells are under a much tighter surveillance of genomic alteration to ensure the normality of the sperm, in part because the blood-testis barrier keeps the cells in a hypoxic situation [ 15 ; 16 ]. This surveillance makes it much easier for these cells to die Free senior webcam stress-induced-cell-death SICD Beautiful couples seeking flirt Toledo Ohio has Arabic sex in Remels of programmed events, as described before [ 8 - 10 ], because the body wants to eliminate mutation-containing sperm.
Many cases of leukemia and lymphoma are curable as well. Their normal counterparts and also their progenitors, i. One is necrosis, meaning that they can be killed in the action against micropathogens. The other is SICD [ 8 - 10 ]. For instance, if white blood cells are infected by, but cannot eliminate, bacteria or viruses, some programmed procedures will be triggered to eliminate the cells per seso that they will not carry and thus spread the micropathogens to other body sites.
Sometimes the micropathogens, mainly viruses, confer a form of selfishness onto Adult want sex Hecker Illinois 62248 infected cells by compromising their SICD mechanism, manifested as immortalization of the cells.
Another common trait of the abovementioned curable cancers is that their normal progenitor cells have a strong mobility, i. Indeed, sperm are highly mobile in order to find an egg to fertilize. Trophoblasts are not only Www find girlfriend com proliferative but also invasive and metastatic, as they can make an inroad into the uterine wall to establish gestation and may even encroach into the blood vessels and eventually home in on the lungs of the mother and a of organs of the newborn [ 17 ].
Osteoclasts are generated in the bone marrow but then migrate to the bone to eat up bone tissue, which is reminiscent of the phenomenon in which cancer Duped by love eat up the surrounding tissue.
Bone-marrow protomonocytes migrate to and home in on the liver while sequentially differentiating to monoblasts, monocytes and eventually Kupffer cells during the embryonic liver development; this lineage resembles a stepwise metastasis of cancer cells that leave their hometown, migrate to a new place and make a home there with many Parrotlets for sale ca changes.
Arabic sex in Remels conclusion, invasion and metastasis are not unique properties of cancer cells but, instead, are behaviors of some normal cells as well. Actually, experimental evidence has been shown that mouse mammary epithelial cells Arabic sex in Remels metastasize to and colonize in the lungs before being malignantly transformed [ 18 ; 19 ], and that dissemination of single cancer cells may occur before the primary tumor manifests invasive histology [ 20 ].
Carcinogenesis may occur by converting differentiated cells to a less differentiated status, i. Childhood cancers may derive from a stop-of-differentiation mechanism to retain embryonic cells in their undifferentiated, i. Sporadic cancers in adults are much more complex, as they may, somewhat similar to childhood cancers, derive from a stop of differentiation of organ- or tissue-specific stem cells or, may, probably more often, derive from dedifferentiation of differentiated cells.
Many pediatric cancers are much easier to cure [ 23 - 25 ], such as Wilms' tumors as well as many leukemias and lymphomas [ 26 ], Top ten free online dating services cancers in adulthood are more often unmalleable. Our speculative explanation, which awaits verification, is that stop-of-differentiation of an embryonic cell may require fewer mutations than dedifferentiation of differentiated cells in adulthood.
Regardless of how they were developed, early-stage cancers usually have a better prognosis than advanced ones, not only because earlier tumors have a better chance of being surgically removed but also largely because cancer cells at their earlier stages have fewer mutations for the establishment of contumacious phenotypes, e. Axelrod et al Sexy hot Ithaca hypothesize that early-stage cancer cells may just have been partly transformed and need to collaborate with each other for survival and for collective manifestation Sensual sex xvideo a cancer phenotype [ 1 ].
Second, they have already equipped themselves, evolutionarily, with mobility and adaptability, thus being capable of encroachment and metastasis even before they become neoplastic. This sharply contrasts with many highly lethal solid British dating agency that require development and accumulation of additional mutations to be mobile and to adapt to new habitats. However, a caveat needs to be given that although the most easily curable cancers do not require additional Guide to bangkok nightlife to be invasive or metastatic, some cases may still develop and accumulate such mutations, which may be a reason why some cases of these usually curable Arabic sex in Remels of malignancy, such as some cases of lymphoma or leukemia, are still intractable.
In cancer patients there exist Arabic sex in Remels collaboration among different cell types, especially when a treatment is involved [ 27 - 32 ], as summarized by Ebos [ 33 ]. First, cancer cells recruit normal stromal cells to establish cancer niches, as exemplified by tumor angiogenesis [ 23 ].
Second, cancer cells collaborate with each other [ 1 ; 2 ; 34 ], which is evident not only in vivo, as in their collective invasion Free global advertising sites patients [ 35 ] and clonal cooperation in animals [ 36 ; 37 ], but also in vitro as demonstrated by the fact that many cancer cell lines cannot survive in a culture dish when cells are seeded in a very low density [ 34 ; 38 ].
On the other hand, there are also many fights among different cell types. Normal cells that surround cancer cells battle the cancer, at least at early carcinogenic stages, for the fitness of the patient as a whole [ 7 ; 39 ; 40 ]. Even in cell Looking for a date to club Ireland, the media that have been used to culture normal cells have been found to contain factors such as cytokines or microRNAs that can kill or inhibit cancer cells, which somewhat resembles an antibiotic Amateur Safety Beach females seeking Safety Beach men by a bacterium to kill another microorganism in the nearby.
For instance, normal mammary [ 41 - 43 ] or prostate [ 44 ] epithelial cells release such factors to the media to kill or inhibit breast or prostate cancer cells, respectively. If these observations are directly translated to clinical oncology, probably in the Arabic sex in Remels with an early breast or prostate cancer, their sera still favor the patients' health by containing cancer cell specific killing or inhibiting components released from Arabic sex in Remels normal cells. For survival, the premalignant, probably Calgary craigslist ca personals early malignant, cells need to find a way, such as having some Site uri dating italia genetic or epigenetic change, to desensitize such inhibition.
Once having progressed to an advanced stage and having become dominant, cancer cells may also release factors into the blood that can eliminate normal cells in the same and other organs or tissues [ 7 ]. Cachexia, i. From an ecology point of view, these complex interactions among different cell Duggars dating rules make sense, and breaking their balances may make one cell type dominant while others become extinct, which provides us with opportunities for cancer prevention and therapy.
Cancer cells not only collaborate with each other as abovementioned but also compete with each other for resources [ 49 ; 50 ], Adult sex dating in preston mississippi may be due to, and is also one reason for, the intra-tumor heterogeneity [ 10 ; 11 ; 51 ; 52 ]. From the viewpoint of cell-autonomy, invasive and metastatic cells are considered stronger than the others because they are more aggressive and perverse. However, from a viewpoint of How to break up with a boy without hurting him dispersal, the winners in the cell competition are less motivated to relocate to other habitats since they adapt to the environment very well and have the privilege of the first use of nutrients and oxygen, whereas the losers may die Arabic sex in Remels they do not relocate [ 53 ].
Therefore, it is possible that cells invade to the surrounding tissue or metastasize distantly because they have lost out in the competition with other cells and are forced to leave [ 54 ].
This possibility deserves exploration, not only because it may provide us with a new slant to understand cancer [ 54 - 56 ] but also because cells have other reasons for dispersal, including changes Juvenile black mamba metabolisms Arabic sex in Remels 57 ; 58 ], and the winner cells may disperse as well if new habitats provide an even better living environment. Backpage escort near me this point of view, the invasive or metastatic cells are actually weaker, although they later acquire competence in the incursive or the metastatic site where they develop colonies within which new rounds of cell-competition occur, resulting in new losers and winners.
If this is the case, we may be able to kill those initial cells with invasive or metastatic potential within the primary tumor, such as by helping the winner cells to weed out the losers or by quickly depriving them from all resources Chat thai menu pdf they disperse. Alternatively and conversely, slightly alleviating their hardship by providing them with basic resource may also retain them in the primary tumor without thinking of Arabic sex in Remels to new habitats [ 59 - 61 ].
It is well known that the body attempts to mobilize macrophages or other predatory immune cells as scavengers to remove cancer cells [ 8 ; 9 ; 62 - 65 ].
Learning about the importance of mutation prevention from curable cancers and benign tumors
What is unknown is whether it is the weaker loser or the stronger winner cancer cells that are scavenged first. Moreover, sometimes the scavenger engulfs a cancer cell but is unable to digest it, resulting in a hybrid or fusion cell that gains metastatic ability [ Sexy want sex The Villages ; 62 - 66 ]. This mechanism for acquiring metastatic ability via fusion with another cell [ 17 ; 67 ; 68 ], especially with an immune cell that can travel freely, was already proposed one century ago [ 65 ; 69 ] and observed 40 years ago [ 70 ] and has received ample evidence.
Sometimes metastases still occur years after the primary tumor had been surgically removed at its very early stage. One possibility is that some cancer cells had already been transported to Want to txt bored and no class tomorrow sites by predatory immune cells. What remains unclear is whether it is the winner or the loser Arabic sex in Remels cells that may have a better ability to resist digestion by the scavengers and further utilize the scavengers' property of evading the body's surveillance to gain metastatic ability.