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A Transition Zone Showing Highly Discontinuous or Alternating Levels of Stem Cell and Proliferation Markers Characterizes the Development of PTEN-Haploinsufficient Colorectal Cancer.

Arvai KJ, Hsu YH, Lee LA, Jones D - PLoS ONE (2015)

Bottom Line: These zones also show parallel alternating levels and/or subcellular localization of multiple cancer stem/progenitor cell (CSC) markers, including β-catenin/CTNNB1, ALDH1, and CD44.There were no significant differences in the levels of KRAS mutation or CTNNB1 mutation in CSC-like tumors as compared to unselected CRC cases.In conclusion, we have identified a distinctive CSC-like pre-invasive transition zone in PTEN-haploinsufficient CRC that shows convergent on-off regulation of the PTEN/AKT, TGF-β/SMAD and Wnt/β-catenin pathways.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Quest Diagnostics Nichols Institute, Chantilly, Virginia, United States of America.

ABSTRACT

Background: Stepwise acquisition of oncogene mutations and deletion/inactivation of tumor suppressor genes characterize the development of colorectal cancer (CRC). These genetic events interact with discrete morphologic transitions from hyperplastic mucosa to adenomatous areas, followed by in situ malignant transformation and finally invasive carcinoma. The goal of this study was to identify tissue markers of the adenoma-carcinoma morphogenetic transitions in CRC.

Methods and findings: We analyzed the patterns of expression of growth regulatory and stem cell markers across these distinct morphologic transition zones in 735 primary CRC tumors. In 202 cases with preserved adenoma-adenocarcinoma transition, we identified, in 37.1% of cases, a zone of adenomatous epithelium, located immediately adjacent to the invasive component, that showed rapidly alternating intraglandular stretches of PTEN+ and PTEN- epithelium. This zone exactly overlapped with similar alternating expression of Ki-67 and inversely with the transforming growth factor-beta (TGF-β) growth regulator SMAD4. These zones also show parallel alternating levels and/or subcellular localization of multiple cancer stem/progenitor cell (CSC) markers, including β-catenin/CTNNB1, ALDH1, and CD44. PTEN was always re-expressed in the invasive tumor in these cases, unlike those with complete loss of PTEN expression. Genomic microarray analysis of CRC with prominent CSC-like expansions demonstrated a high frequency of PTEN genomic deletion/haploinsufficiency in tumors with CSC-like transition zones (62.5%) but not in tumors with downregulated but non-alternating PTEN expression (14.3%). There were no significant differences in the levels of KRAS mutation or CTNNB1 mutation in CSC-like tumors as compared to unselected CRC cases.

Conclusions: In conclusion, we have identified a distinctive CSC-like pre-invasive transition zone in PTEN-haploinsufficient CRC that shows convergent on-off regulation of the PTEN/AKT, TGF-β/SMAD and Wnt/β-catenin pathways. This bottleneck-like zone is usually followed by the emergence of invasive tumors with intact PTEN expression but dysregulated TP53 and uniformly high proliferation rates.

No MeSH data available.


Related in: MedlinePlus

PTEN deletion demonstrated by microarray and FISH in CSC-like tumors.(A) Oligonucleotide/SNP array results show frequent deletion (red lines) of the PTEN locus on chromosome 10 (black dotted arrow) in CRC with prominent CSC-like transition zones (blue background) and in tumors with complete PTEN loss by IHC (pink background) as compared to those with uniform PTEN downmodulation or normal expression (white and yellow background). Cases with deletions of the p arm of chromosome 17 encompassing TP53 (middle) and deletions of chromosome 18 (right) were commonly noted in CRC and were independent of PTEN IHC pattern. (B-E) Comparison of PTEN IHC and FISH in a CSC-like tumor (Case 1 from S2 Table). (B) High magnification of PTEN IHC with the typical alternating expression pattern at the transition zone. (C) The matched PTEN FISH image shows a heterogeneous pattern of loss of PTEN and chromosome 10 copy number in the tumor epithelial cells. (D) PTEN IHC in the invasive ACA away from the transition shows uniform expression. (E) FISH analysis in the invasive ACA area away from the transition show a uniform pattern of one copy PTEN loss. (F) PTEN IHC in a CRC case with absent PTEN staning. (G) PTEN FISH in a serial section of the same tumor as (F) showing homozygous PTEN deletion. The underlying stromal cells at the green arrow show normal PTEN copy number.
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pone.0131108.g004: PTEN deletion demonstrated by microarray and FISH in CSC-like tumors.(A) Oligonucleotide/SNP array results show frequent deletion (red lines) of the PTEN locus on chromosome 10 (black dotted arrow) in CRC with prominent CSC-like transition zones (blue background) and in tumors with complete PTEN loss by IHC (pink background) as compared to those with uniform PTEN downmodulation or normal expression (white and yellow background). Cases with deletions of the p arm of chromosome 17 encompassing TP53 (middle) and deletions of chromosome 18 (right) were commonly noted in CRC and were independent of PTEN IHC pattern. (B-E) Comparison of PTEN IHC and FISH in a CSC-like tumor (Case 1 from S2 Table). (B) High magnification of PTEN IHC with the typical alternating expression pattern at the transition zone. (C) The matched PTEN FISH image shows a heterogeneous pattern of loss of PTEN and chromosome 10 copy number in the tumor epithelial cells. (D) PTEN IHC in the invasive ACA away from the transition shows uniform expression. (E) FISH analysis in the invasive ACA area away from the transition show a uniform pattern of one copy PTEN loss. (F) PTEN IHC in a CRC case with absent PTEN staning. (G) PTEN FISH in a serial section of the same tumor as (F) showing homozygous PTEN deletion. The underlying stromal cells at the green arrow show normal PTEN copy number.

Mentions: The frequency of genomic loss at 10q/PTEN as assessed by OSA (10/16; 62.5%) was much higher in CRC with prominent CSC-like expansion, as defined by the PTEN IHC pattern, than in cases with uniform PTEN expression (1/16; 6.3%, p = .0007) (Fig 4A). In CSC-like cases, the frequency of PTEN deletion was even higher (13/17; 76.4%) when assayed by FISH. Using FISH, we also assessed the genetic complement in individual cells within the CSC-like zone itself and in the invasive component. These studies demonstrated much more variable deletion of chromosome 10 and the PTEN locus whereas in the invasive ACA away from the junction, the pattern of PTEN FISH was more uniformly heterozygous deletion (Fig 4B–4E and S2 Table).


A Transition Zone Showing Highly Discontinuous or Alternating Levels of Stem Cell and Proliferation Markers Characterizes the Development of PTEN-Haploinsufficient Colorectal Cancer.

Arvai KJ, Hsu YH, Lee LA, Jones D - PLoS ONE (2015)

PTEN deletion demonstrated by microarray and FISH in CSC-like tumors.(A) Oligonucleotide/SNP array results show frequent deletion (red lines) of the PTEN locus on chromosome 10 (black dotted arrow) in CRC with prominent CSC-like transition zones (blue background) and in tumors with complete PTEN loss by IHC (pink background) as compared to those with uniform PTEN downmodulation or normal expression (white and yellow background). Cases with deletions of the p arm of chromosome 17 encompassing TP53 (middle) and deletions of chromosome 18 (right) were commonly noted in CRC and were independent of PTEN IHC pattern. (B-E) Comparison of PTEN IHC and FISH in a CSC-like tumor (Case 1 from S2 Table). (B) High magnification of PTEN IHC with the typical alternating expression pattern at the transition zone. (C) The matched PTEN FISH image shows a heterogeneous pattern of loss of PTEN and chromosome 10 copy number in the tumor epithelial cells. (D) PTEN IHC in the invasive ACA away from the transition shows uniform expression. (E) FISH analysis in the invasive ACA area away from the transition show a uniform pattern of one copy PTEN loss. (F) PTEN IHC in a CRC case with absent PTEN staning. (G) PTEN FISH in a serial section of the same tumor as (F) showing homozygous PTEN deletion. The underlying stromal cells at the green arrow show normal PTEN copy number.
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Related In: Results  -  Collection

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pone.0131108.g004: PTEN deletion demonstrated by microarray and FISH in CSC-like tumors.(A) Oligonucleotide/SNP array results show frequent deletion (red lines) of the PTEN locus on chromosome 10 (black dotted arrow) in CRC with prominent CSC-like transition zones (blue background) and in tumors with complete PTEN loss by IHC (pink background) as compared to those with uniform PTEN downmodulation or normal expression (white and yellow background). Cases with deletions of the p arm of chromosome 17 encompassing TP53 (middle) and deletions of chromosome 18 (right) were commonly noted in CRC and were independent of PTEN IHC pattern. (B-E) Comparison of PTEN IHC and FISH in a CSC-like tumor (Case 1 from S2 Table). (B) High magnification of PTEN IHC with the typical alternating expression pattern at the transition zone. (C) The matched PTEN FISH image shows a heterogeneous pattern of loss of PTEN and chromosome 10 copy number in the tumor epithelial cells. (D) PTEN IHC in the invasive ACA away from the transition shows uniform expression. (E) FISH analysis in the invasive ACA area away from the transition show a uniform pattern of one copy PTEN loss. (F) PTEN IHC in a CRC case with absent PTEN staning. (G) PTEN FISH in a serial section of the same tumor as (F) showing homozygous PTEN deletion. The underlying stromal cells at the green arrow show normal PTEN copy number.
Mentions: The frequency of genomic loss at 10q/PTEN as assessed by OSA (10/16; 62.5%) was much higher in CRC with prominent CSC-like expansion, as defined by the PTEN IHC pattern, than in cases with uniform PTEN expression (1/16; 6.3%, p = .0007) (Fig 4A). In CSC-like cases, the frequency of PTEN deletion was even higher (13/17; 76.4%) when assayed by FISH. Using FISH, we also assessed the genetic complement in individual cells within the CSC-like zone itself and in the invasive component. These studies demonstrated much more variable deletion of chromosome 10 and the PTEN locus whereas in the invasive ACA away from the junction, the pattern of PTEN FISH was more uniformly heterozygous deletion (Fig 4B–4E and S2 Table).

Bottom Line: These zones also show parallel alternating levels and/or subcellular localization of multiple cancer stem/progenitor cell (CSC) markers, including β-catenin/CTNNB1, ALDH1, and CD44.There were no significant differences in the levels of KRAS mutation or CTNNB1 mutation in CSC-like tumors as compared to unselected CRC cases.In conclusion, we have identified a distinctive CSC-like pre-invasive transition zone in PTEN-haploinsufficient CRC that shows convergent on-off regulation of the PTEN/AKT, TGF-β/SMAD and Wnt/β-catenin pathways.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Quest Diagnostics Nichols Institute, Chantilly, Virginia, United States of America.

ABSTRACT

Background: Stepwise acquisition of oncogene mutations and deletion/inactivation of tumor suppressor genes characterize the development of colorectal cancer (CRC). These genetic events interact with discrete morphologic transitions from hyperplastic mucosa to adenomatous areas, followed by in situ malignant transformation and finally invasive carcinoma. The goal of this study was to identify tissue markers of the adenoma-carcinoma morphogenetic transitions in CRC.

Methods and findings: We analyzed the patterns of expression of growth regulatory and stem cell markers across these distinct morphologic transition zones in 735 primary CRC tumors. In 202 cases with preserved adenoma-adenocarcinoma transition, we identified, in 37.1% of cases, a zone of adenomatous epithelium, located immediately adjacent to the invasive component, that showed rapidly alternating intraglandular stretches of PTEN+ and PTEN- epithelium. This zone exactly overlapped with similar alternating expression of Ki-67 and inversely with the transforming growth factor-beta (TGF-β) growth regulator SMAD4. These zones also show parallel alternating levels and/or subcellular localization of multiple cancer stem/progenitor cell (CSC) markers, including β-catenin/CTNNB1, ALDH1, and CD44. PTEN was always re-expressed in the invasive tumor in these cases, unlike those with complete loss of PTEN expression. Genomic microarray analysis of CRC with prominent CSC-like expansions demonstrated a high frequency of PTEN genomic deletion/haploinsufficiency in tumors with CSC-like transition zones (62.5%) but not in tumors with downregulated but non-alternating PTEN expression (14.3%). There were no significant differences in the levels of KRAS mutation or CTNNB1 mutation in CSC-like tumors as compared to unselected CRC cases.

Conclusions: In conclusion, we have identified a distinctive CSC-like pre-invasive transition zone in PTEN-haploinsufficient CRC that shows convergent on-off regulation of the PTEN/AKT, TGF-β/SMAD and Wnt/β-catenin pathways. This bottleneck-like zone is usually followed by the emergence of invasive tumors with intact PTEN expression but dysregulated TP53 and uniformly high proliferation rates.

No MeSH data available.


Related in: MedlinePlus