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==Overview==
==Overview==
The pathogenesis of colorectal carcinoma (CRC) involves the molecular pathways for both sporadic and colitis-associated CRC. Sporadic instability originates from the [[epithelial cells]] that line the [[colon]] or [[rectum]]. Colitis-associated CRC includes genetic instability, [[Epigenetic|epigenetic alteration]], [[chronic inflammation]], [[oxidative stress]], and intestinal [[microbiota]]. Right-sided and left-sided tumors differ in their [[gross pathology]] depending on glandular architecture, cellular [[pleomorphism]], and mucosecretion of the predominant pattern. [[Adenocarcinoma]] may present in three degrees of differentiation: well, moderately, and poorly differentiated.
The pathogenesis of colorectal carcinoma (CRC) involves the molecular pathways for both sporadic and colitis-associated CRC. Sporadic instability originates from the [[epithelial cells]] that line the [[colon]] or [[rectum]]. Colitis-associated CRC includes genetic instability, [[Epigenetic|epigenetic alteration]], [[chronic inflammation]], [[oxidative stress]], and intestinal [[microbiota]]. According to the World Health Organization (WHO) histological classification, most colorectal tumors are carcinomas of which almost 90% are adenocarcinomas.


==Pathogenesis==
==Pathogenesis==
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The picture below depicts the molecular pathogenesis of sporadic colon cancer:<ref name="Kim2014">{{cite journal|last1=Kim|first1=Eun Ran|title=Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis|journal=World Journal of Gastroenterology|volume=20|issue=29|year=2014|pages=9872|issn=1007-9327|doi=10.3748/wjg.v20.i29.9872}}</ref>
The picture below depicts the molecular pathogenesis of sporadic colon cancer:<ref name="Kim2014">{{cite journal|last1=Kim|first1=Eun Ran|title=Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis|journal=World Journal of Gastroenterology|volume=20|issue=29|year=2014|pages=9872|issn=1007-9327|doi=10.3748/wjg.v20.i29.9872}}</ref>
 
[[Image:Sporadic Colon Cancer3.jpg|center|1000x1000px|frame|Molecular pathogenesis of sporadic colon cancer, (ɔ) Image courtesy of WikiDoc.org]]
[[Image:Sporadic Colon Cancer3.jpg|right|1000x1000px|frame|Molecular pathogenesis of sporadic colon cancer, (ɔ) Image courtesy of WikiDoc.org]]
 
Sporadic colorectal cancer originates from the [[epithelial cells]] that line the [[colon]] or [[rectum]]; it may involve the following:<ref name="pmid20018966">{{cite journal| author=Markowitz SD, Bertagnolli MM| title=Molecular origins of cancer: Molecular basis of colorectal cancer. | journal=N Engl J Med | year= 2009 | volume= 361 | issue= 25 | pages= 2449-60 | pmid=20018966 | doi=10.1056/NEJMra0804588 | pmc=PMC2843693 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20018966  }} </ref>
Sporadic colorectal cancer originates from the [[epithelial cells]] that line the [[colon]] or [[rectum]]; it may involve the following:<ref name="pmid20018966">{{cite journal| author=Markowitz SD, Bertagnolli MM| title=Molecular origins of cancer: Molecular basis of colorectal cancer. | journal=N Engl J Med | year= 2009 | volume= 361 | issue= 25 | pages= 2449-60 | pmid=20018966 | doi=10.1056/NEJMra0804588 | pmc=PMC2843693 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20018966  }} </ref>
*'''[[APC gene]]'''
*'''[[APC gene]]'''
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The picture below depicts the molecular pathogenesis of colitis-associated colon cancer:<ref name="Kim2014">{{cite journal|last1=Kim|first1=Eun Ran|title=Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis|journal=World Journal of Gastroenterology|volume=20|issue=29|year=2014|pages=9872|issn=1007-9327|doi=10.3748/wjg.v20.i29.9872}}</ref>
The picture below depicts the molecular pathogenesis of colitis-associated colon cancer:<ref name="Kim2014">{{cite journal|last1=Kim|first1=Eun Ran|title=Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis|journal=World Journal of Gastroenterology|volume=20|issue=29|year=2014|pages=9872|issn=1007-9327|doi=10.3748/wjg.v20.i29.9872}}</ref>


[[Image:Colitis-associated colon cancer.jpg|800x800px]]
[[Image:Colitis-associated colon cancer.jpg|center|800x800px|frame|Molecular pathogenesis of colitis-associated colon cancer, (ɔ) Image courtesy of WikiDoc.org]]


At a [[microbiological]] level, the development of colitis-associated colorectal cancers (CRC) can be linked to defects within the [[cell cycle]].<ref name="pmid21190461">{{cite journal |author=Scully R |title=The spindle-assembly checkpoint, aneuploidy, and gastrointestinal cancer |journal=[[The New England Journal of Medicine]] |volume=363 |issue=27 |pages=2665–6 |year=2010|pmid=21190461 |doi=10.1056/NEJMe1008017 |url=http://www.nejm.org/doi/abs/10.1056/NEJMe1008017?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed |accessdate=2011-12-12}}</ref>  
At a [[microbiological]] level, the development of colitis-associated colorectal cancers (CRC) can be linked to defects within the [[cell cycle]].<ref name="pmid21190461">{{cite journal |author=Scully R |title=The spindle-assembly checkpoint, aneuploidy, and gastrointestinal cancer |journal=[[The New England Journal of Medicine]] |volume=363 |issue=27 |pages=2665–6 |year=2010|pmid=21190461 |doi=10.1056/NEJMe1008017 |url=http://www.nejm.org/doi/abs/10.1056/NEJMe1008017?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed |accessdate=2011-12-12}}</ref>  
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*'''Intestinal [[microbiota]]'''<ref name="pmid11472326">{{cite journal| author=O'Mahony L, Feeney M, O'Halloran S, Murphy L, Kiely B, Fitzgibbon J et al.| title=Probiotic impact on microbial flora, inflammation and tumour development in IL-10 knockout mice. | journal=Aliment Pharmacol Ther | year= 2001 | volume= 15 | issue= 8 | pages= 1219-25 | pmid=11472326 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11472326  }} </ref>
*'''Intestinal [[microbiota]]'''<ref name="pmid11472326">{{cite journal| author=O'Mahony L, Feeney M, O'Halloran S, Murphy L, Kiely B, Fitzgibbon J et al.| title=Probiotic impact on microbial flora, inflammation and tumour development in IL-10 knockout mice. | journal=Aliment Pharmacol Ther | year= 2001 | volume= 15 | issue= 8 | pages= 1219-25 | pmid=11472326 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11472326  }} </ref>
**The Modification of enteric flora by probiotic [[lactobacilli]] is a proposed mechanism that may contribute to the development of colitis-associated cancer.
**The Modification of enteric flora by probiotic [[lactobacilli]] is a proposed mechanism that may contribute to the development of colitis-associated cancer.
==Genetics==
==Genetics==
From a genetic standpoint, colorectal cancer can be divided into three categories:<ref name="pmid25276405">{{cite journal| author=Schlussel AT, Gagliano RA, Seto-Donlon S, Eggerding F, Donlon T, Berenberg J et al.| title=The evolution of colorectal cancer genetics-Part 1: from discovery to practice. | journal=J Gastrointest Oncol | year= 2014 | volume= 5 | issue= 5 | pages= 326-35 | pmid=25276405 | doi=10.3978/j.issn.2078-6891.2014.069 | pmc=PMC4173047 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25276405  }} </ref>
From a genetic standpoint, colorectal cancer can be divided into three categories:<ref name="pmid25276405">{{cite journal| author=Schlussel AT, Gagliano RA, Seto-Donlon S, Eggerding F, Donlon T, Berenberg J et al.| title=The evolution of colorectal cancer genetics-Part 1: from discovery to practice. | journal=J Gastrointest Oncol | year= 2014 | volume= 5 | issue= 5 | pages= 326-35 | pmid=25276405 | doi=10.3978/j.issn.2078-6891.2014.069 | pmc=PMC4173047 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25276405  }} </ref>
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==Gross Pathology==
==Gross Pathology==
*Right-sided tumors (ascending colon and [[cecum]]) tends to grow outwards from one location in the bowel wall (exophytic)
*On gross pathology, a polypoid or fungating exophytic (growing outwards) lesion is characteristic of right-sided colorectal tumors including the ascending colon and cecum.<ref name="pmid21969498">{{cite journal| author=Weiss JM, Pfau PR, O'Connor ES, King J, LoConte N, Kennedy G et al.| title=Mortality by stage for right- versus left-sided colon cancer: analysis of surveillance, epidemiology, and end results--Medicare data. | journal=J Clin Oncol | year= 2011 | volume= 29 | issue= 33 | pages= 4401-9 | pmid=21969498 | doi=10.1200/JCO.2011.36.4414 | pmc=3221523 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21969498  }}</ref>
 
*Left-sided tumours tend to be circumferential and annular producing an "apple-core" appearance on barium enema x-ray.<ref name="pmid21969498" />
*Left-sided tumours tend to be circumferential


[[Image:Colonic carcinoid (1) Endoscopic resection.jpg|thumb|right|200px|Histopathologic image of colonic carcinoid stained by hematoxylin and eosin. - By No machine-readable author provided. KGH assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=453828]]
[[Image:Colonic carcinoid (1) Endoscopic resection.jpg|thumb|right|200px|Histopathologic image of colonic carcinoid stained by hematoxylin and eosin. - By No machine-readable author provided. KGH assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=453828]]
==Histology==
==Microscopic Pathology==
*Most tumors affecting the colon are carcinomas, and of these carcinomas almost 90% are adenocarcinomas.
According to the World Health Organization (WHO) histological classification, most colorectal tumors are carcinomas of which almost 90% are adenocarcinomas:<ref name="pmid10888773">{{cite journal| author=Compton CC, Fielding LP, Burgart LJ, Conley B, Cooper HS, Hamilton SR et al.| title=Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999. | journal=Arch Pathol Lab Med | year= 2000 | volume= 124 | issue= 7 | pages= 979-94 | pmid=10888773 | doi=10.1043/0003-9985(2000)124<0979:PFICC>2.0.CO;2 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10888773  }}</ref>
*Rarely, tumors of the colon are of other histologic types including hamartomas, neuroendocrine neoplasms, mesenchymal, or lymphomas.
*Carcinomas
*The College of American Pathologists (CAP) and the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) have both recommended the adoption of a two-tiered grading system for CRC and the use of gland formation as the only feature by which grade is assessed.<ref name="pmid10888773">{{cite journal| author=Compton CC, Fielding LP, Burgart LJ, Conley B, Cooper HS, Hamilton SR et al.| title=Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999. | journal=Arch Pathol Lab Med | year= 2000 | volume= 124 | issue= 7 | pages= 979-94 | pmid=10888773 | doi=10.1043/0003-9985(2000)124<0979:PFICC>2.0.CO;2 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10888773  }}</ref>  
**Adenocarcinoma
*Tumor cells form irregular tubular structures, harboring pleuristratification, multiple lumens, and reduced [[stroma]]
**Mucinous adenocarcinoma
*Sometimes, tumor cells are discohesive and secrete [[mucus]], which invades the [[interstitium]] producing large pools of [[mucus]]/[[colloid]] (optically "empty" spaces)
**Signet-ring cell carcinoma
*If the mucus remains inside the tumor cell, it pushes the nucleus at the periphery ([[Signet ring cell|signet-ring cell]])
**Small cell carcinoma
 
**Adenosquamous carcinoma
**Squamous cell  
**Medullary carcinoma
**Undifferentiated carcinoma
*Neuroendocrine neoplasms
*Hamartomas
*Mesenchymas tumors
*Lymphomas




<br clear="left" />
<br clear="left" />
===Grades of Colorectal Cancer===
===References===
The grade describes how closely the cancer looks like normal tissue when seen under a [[microscope]]. This is sometimes used to distinguish whether a patient should get [[adjuvant treatment]] with [[chemotherapy]] after [[surgery]].
*Grade 1 - Well differentiated
*Grade 2 - Moderately differentiated
*Grade 3 - Poorly differentiated
*Grade 4 - Undifferentiated
 
===Video===
 
{{#ev:youtube|Sh65aXndqXk}}
 
==References==
{{Reflist|2}}
{{Reflist|2}}



Latest revision as of 16:14, 28 February 2019

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To view the pathophysiology of familial adenomatous polyposis (FAP), click here
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Saarah T. Alkhairy, M.D., Roukoz A. Karam, M.D.[2], Elliot B. Tapper, M.D.

Overview

The pathogenesis of colorectal carcinoma (CRC) involves the molecular pathways for both sporadic and colitis-associated CRC. Sporadic instability originates from the epithelial cells that line the colon or rectum. Colitis-associated CRC includes genetic instability, epigenetic alteration, chronic inflammation, oxidative stress, and intestinal microbiota. According to the World Health Organization (WHO) histological classification, most colorectal tumors are carcinomas of which almost 90% are adenocarcinomas.

Pathogenesis

The pathogenesis of colorectal carcinoma (CRC) involves the molecular pathways for both sporadic and colitis-associated CRC.

Sporadic colorectal cancers

The picture below depicts the molecular pathogenesis of sporadic colon cancer:[1]

Molecular pathogenesis of sporadic colon cancer, (ɔ) Image courtesy of WikiDoc.org

Sporadic colorectal cancer originates from the epithelial cells that line the colon or rectum; it may involve the following:[2]

  • Produces the APC protein, which prevents the accumulation of β-catenin protein (responsible for stem cell renewal)
  • Mutation of the APC protein leads to the accumulation of β-catenin protein and causes inappropriately high levels of stem cell renewal.
  • Produces the p53 protein, which monitors cell division and promotes apoptosis if there are cell defects
  • Mutations result in loss of control over cell division or apoptosis
  • TGF-β and DCC (Deleted in Colorectal Cancer)
  • Usually responsible for apoptosis, but deactivated in colorectal cancer

Colitis-associated colorectal cancers

The picture below depicts the molecular pathogenesis of colitis-associated colon cancer:[1]

Molecular pathogenesis of colitis-associated colon cancer, (ɔ) Image courtesy of WikiDoc.org

At a microbiological level, the development of colitis-associated colorectal cancers (CRC) can be linked to defects within the cell cycle.[3]

Although it is poorly understood, the following five factors may be responsible for its neoplastic changes:[1]

  • Intestinal microbiota[9]
    • The Modification of enteric flora by probiotic lactobacilli is a proposed mechanism that may contribute to the development of colitis-associated cancer.

Genetics

From a genetic standpoint, colorectal cancer can be divided into three categories:[10]

  • Sporadic (75% of cases)
    • No indication of a hereditary component
  • Familial (20% of cases)
  • Hereditary (10% of cases)
Appearance of the inside of the colon showing one invasive colorectal carcinoma (the crater-like, reddish, irregularly shaped tumor). - Source: librepathology.org

Gross Pathology

  • On gross pathology, a polypoid or fungating exophytic (growing outwards) lesion is characteristic of right-sided colorectal tumors including the ascending colon and cecum.[11]
  • Left-sided tumours tend to be circumferential and annular producing an "apple-core" appearance on barium enema x-ray.[11]
Histopathologic image of colonic carcinoid stained by hematoxylin and eosin. - By No machine-readable author provided. KGH assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=453828

Microscopic Pathology

According to the World Health Organization (WHO) histological classification, most colorectal tumors are carcinomas of which almost 90% are adenocarcinomas:[12]

  • Carcinomas
    • Adenocarcinoma
    • Mucinous adenocarcinoma
    • Signet-ring cell carcinoma
    • Small cell carcinoma
    • Adenosquamous carcinoma
    • Squamous cell
    • Medullary carcinoma
    • Undifferentiated carcinoma
  • Neuroendocrine neoplasms
  • Hamartomas
  • Mesenchymas tumors
  • Lymphomas



References

  1. 1.0 1.1 1.2 Kim, Eun Ran (2014). "Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis". World Journal of Gastroenterology. 20 (29): 9872. doi:10.3748/wjg.v20.i29.9872. ISSN 1007-9327.
  2. Markowitz SD, Bertagnolli MM (2009). "Molecular origins of cancer: Molecular basis of colorectal cancer". N Engl J Med. 361 (25): 2449–60. doi:10.1056/NEJMra0804588. PMC 2843693. PMID 20018966.
  3. Scully R (2010). "The spindle-assembly checkpoint, aneuploidy, and gastrointestinal cancer". The New England Journal of Medicine. 363 (27): 2665–6. doi:10.1056/NEJMe1008017. PMID 21190461. Retrieved 2011-12-12.
  4. Zivić R, Bjelaković G, Koraćević D (1975). "[Amino acid constitution of the urine in children with rheumatic fever]". Reumatizam. 22 (1): 21–5. PMID 1118685.
  5. Itzkowitz S (2003). "Colon carcinogenesis in inflammatory bowel disease: applying molecular genetics to clinical practice". J Clin Gastroenterol. 36 (5 Suppl): S70–4, discussion S94-6. PMID 12702969.
  6. Kraus S, Arber N (2009). "Inflammation and colorectal cancer". Curr Opin Pharmacol. 9 (4): 405–10. doi:10.1016/j.coph.2009.06.006. PMID 19589728.
  7. Elzagheid A, Emaetig F, Alkikhia L, Buhmeida A, Syrjänen K, El-Faitori O; et al. (2013). "High cyclooxygenase-2 expression is associated with advanced stages in colorectal cancer". Anticancer Res. 33 (8): 3137–43. PMID 23898071.
  8. Ullman TA, Itzkowitz SH (2011). "Intestinal inflammation and cancer". Gastroenterology. 140 (6): 1807–16. doi:10.1053/j.gastro.2011.01.057. PMID 21530747.
  9. O'Mahony L, Feeney M, O'Halloran S, Murphy L, Kiely B, Fitzgibbon J; et al. (2001). "Probiotic impact on microbial flora, inflammation and tumour development in IL-10 knockout mice". Aliment Pharmacol Ther. 15 (8): 1219–25. PMID 11472326.
  10. Schlussel AT, Gagliano RA, Seto-Donlon S, Eggerding F, Donlon T, Berenberg J; et al. (2014). "The evolution of colorectal cancer genetics-Part 1: from discovery to practice". J Gastrointest Oncol. 5 (5): 326–35. doi:10.3978/j.issn.2078-6891.2014.069. PMC 4173047. PMID 25276405.
  11. 11.0 11.1 Weiss JM, Pfau PR, O'Connor ES, King J, LoConte N, Kennedy G; et al. (2011). "Mortality by stage for right- versus left-sided colon cancer: analysis of surveillance, epidemiology, and end results--Medicare data". J Clin Oncol. 29 (33): 4401–9. doi:10.1200/JCO.2011.36.4414. PMC 3221523. PMID 21969498.
  12. Compton CC, Fielding LP, Burgart LJ, Conley B, Cooper HS, Hamilton SR; et al. (2000). "Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999". Arch Pathol Lab Med. 124 (7): 979–94. doi:10.1043/0003-9985(2000)124<0979:PFICC>2.0.CO;2. PMID 10888773.


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