Can a plasmid cause cancer? According to wikipedia, plasmids are normally present in bacteria

They (plasmids) are normally present in bacteria , and sometimes in eukaryotic organisms such as yeast [(my translation)]

Let's say we inject yeast (by digestive tract) into a H. Sapiens (we will be focused in the yeast's plasmid only). Is it possible for plasmids to get into eukaryotic cells presents in the digestive tract?

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    $\begingroup$ Is it possible for plasmids to get into eukaryotic cells presents in the digestive tract? is a completely different question $\endgroup$ – another 'Homo sapien' Aug 14 '18 at 12:27

Canonically, bacterial plasmids will not replicate in eukaryotic systems, due to a lack of the necessary control (regulatory) elements which will lead to expression.

It is possible though to construct shuttle vectors that can propagate in prokaryotes and eukaryotic cells (e.g. yeast or mammalian cells like the immortal HeLa cervical cancer-derived cell line).

What you are specifically asking is whether horizontal (lateral) gene transfer between prokaryotes and eukaryotes occurs, and whether it has an effect on the eukaryotic cell. This 2016 paper is an excellent and recent article discussing this question.

Can a plasmid cause cancer?

It has never been demonstrated, to my knowledge.

Is it possible for plasmids to get into eukaryotic cells presents in the digestive tract?

Very few bacteria can penetrate a healthy intestinal lining. However, in many disorders of the gastrointestinal system, such as in inflammatory bowel disorders, the intestinal lining is compromised, which certainly allows the passage of prokaryotes and/or DNA into human circulation. However, a functional transfer of plasmids from prokaryotes to eukaryotic cells is not demonstrated. Whether the hypothetical transfer would lead to carcinogenesis is also not demonstrated.

  • $\begingroup$ A wide variety of intestinal bacteria leave their compartment and cause disease at other sites. This happens all the time. Often enough that there is at least one patient in your local hospital for exactly this reason right now :) $\endgroup$ – De Novo Aug 14 '18 at 15:59
  • $\begingroup$ I want to understand what you mean, the comment is unclear in intent. Gut microbes cause disease all over the body, but can they cross a healthy intestinal lining and the gut-blood barrier? And can you give an example of a disease 'at other sites' caused specifically by gut microbe infiltration, so we are on the same page? Gastroenterology is a very rich field and it's not my strongest point and the specifics are, well, quite specific. Cheers! $\endgroup$ – S Pr Aug 15 '18 at 15:27
  • $\begingroup$ The intent of the comment is to correct an error in your answer. Pathogenic enterobacteriaceae often penetrate the intestinal lining. This is a common cause of sepsis, endocarditis, meningitis, and a rare cause of pneumonia (pneumonia that cultures positive for enterobacteriaceae is more often due to aspiration). Certain types of gastroenteritis are caused by invasive infection as well. Your gut is a good barrier most of the time, but gut and mouth bugs often get through. Sometimes the result is transient bacteremia. Sometimes it is disease. $\endgroup$ – De Novo Aug 15 '18 at 16:20
  • $\begingroup$ I stand by the statement that very few bacteria penetrate healthy intestinal lining. Perhaps I should have mentioned it is known that even in healthy individuals, there exist small amounts of viable bacteria in the urine and in healthy blood, even though, in medical circles, both are typically referred to as sterile environments. And, as you say, if any lining is compromised, bacteria and other microbes will certainly access circulation. $\endgroup$ – S Pr Aug 16 '18 at 9:08
  • $\begingroup$ the statement you're standing by is unsourced and disagrees with my medical and infectious disease specialist training, my clinical experience, and basic textbooks on medical microbiology, internal medicine, and infectious disease. $\endgroup$ – De Novo Aug 16 '18 at 17:54

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