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Intratumoral diversity of telomere length in individual neuroblastoma tumors.

Pezzolo A, Pistorio A, Gambini C, Haupt R, Ferraro M, Erminio G, De Bernardi B, Garaventa A, Pistoia V - Oncotarget (2015)

Bottom Line: Neither ALT-mechanism nor hTERT expression correlated with heterogeneous TL. 3) High hTERT expression and ALT positivity were associated with significantly reduced Overall Survival. 4) High hTERT expression predicted relapse irrespective of patient age.Intratumoral diversity in TL represents a novel feature in NB.In conclusion, diversity of TL in individual NB tumors was strongly associated with disease progression and death, suggesting that these findings are of translational relevance.The combination of high hTERT expression and ALT positivity may represent a novel biomarker of poor prognosis that deserves further investigation.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio di Oncologia, Istituto Giannina Gaslini, Genova, Italy.

ABSTRACT
The purpose of the work was to investigate telomere length (TL) and mechanisms involved in TL maintenance in individual neuroblastoma (NB) tumors. Primary NB tumors from 102 patients, ninety Italian and twelve Spanish, diagnosed from 2000 to 2008 were studied. TL was investigated by quantitative fluorescence in situ hybridization (IQ-FISH) that allows to analyze individual cells in paraffin-embedded tissues. Fluorescence intensity of chromosome 2 centromere was used as internal control to normalize TL values to ploidy. Human telomerase reverse transcriptase (hTERT) expression was detected by immunofluorescence in 99/102 NB specimens.The main findings are the following: 1) two intratumoral subpopulations of cancer cells displaying telomeres of different length were identified in 32/102 tumors belonging to all stages. 2) hTERT expression was detected in 99/102 tumors, of which 31 displayed high expression and 68 low expression. Alternative lengthening of telomeres (ALT)-mechanism was present in 60/102 tumors, 20 of which showed high hTERT expression. Neither ALT-mechanism nor hTERT expression correlated with heterogeneous TL. 3) High hTERT expression and ALT positivity were associated with significantly reduced Overall Survival. 4) High hTERT expression predicted relapse irrespective of patient age. Intratumoral diversity in TL represents a novel feature in NB.In conclusion, diversity of TL in individual NB tumors was strongly associated with disease progression and death, suggesting that these findings are of translational relevance. The combination of high hTERT expression and ALT positivity may represent a novel biomarker of poor prognosis that deserves further investigation.

No MeSH data available.


Related in: MedlinePlus

A: ALT positive NB cells showing ALT-associated bright intra-nuclear foci of telomere FISH signals (red) (arrows)Nuclear DNA was counterstained with DAPI (blue). B: Immunofluorescence nuclear labeling for the catalytic subunit of telomerase hTERT (green). C: Variance analysis of TL in relation to presence or absence of ALT and to high or low hTERT expression. D: Kaplan-Meier Event-Free Survival curve for long/normal TL and hTERT expression. E: Kaplan-Meier Event-Free Survival curve for short TL and hTERT expression.
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Figure 3: A: ALT positive NB cells showing ALT-associated bright intra-nuclear foci of telomere FISH signals (red) (arrows)Nuclear DNA was counterstained with DAPI (blue). B: Immunofluorescence nuclear labeling for the catalytic subunit of telomerase hTERT (green). C: Variance analysis of TL in relation to presence or absence of ALT and to high or low hTERT expression. D: Kaplan-Meier Event-Free Survival curve for long/normal TL and hTERT expression. E: Kaplan-Meier Event-Free Survival curve for short TL and hTERT expression.

Mentions: Telomere elongation is operated by telomerase and ALT mechanism, that is based on recombination of telomeric sequences and might cause heterogeneous TL in single cancer cells [10-12]. ALT was detected by FISH analysis [37-39] in 60/102 NB samples tested; one representative experiment is shown in Fig 3A. Sixteen out of 32 (50%) tumors with heterogeneous TL and 44/70 (62.9%) tumors with homogeneous TL were ALT positive (P=0.22). Variable expression of hTERT was detected by immunofluorescence in 99/102 (97%) NB specimens tested (Fig 3B). Thirty-one out of 99 (31.3%) tumors displayed high hTERT expression [(>0.398 units of fluorescence intensity (FI) while 68/99 (68.7%) showed low hTERT expression (≤0.398 FI). Twenty of 31 cases with high hTERT expression (64.5%) and 40/68 with low hTERT expression (58.8%) were ALT positive, indicating lack of correlation between ALT mechanism and hTERT expression levels (P=0.59).


Intratumoral diversity of telomere length in individual neuroblastoma tumors.

Pezzolo A, Pistorio A, Gambini C, Haupt R, Ferraro M, Erminio G, De Bernardi B, Garaventa A, Pistoia V - Oncotarget (2015)

A: ALT positive NB cells showing ALT-associated bright intra-nuclear foci of telomere FISH signals (red) (arrows)Nuclear DNA was counterstained with DAPI (blue). B: Immunofluorescence nuclear labeling for the catalytic subunit of telomerase hTERT (green). C: Variance analysis of TL in relation to presence or absence of ALT and to high or low hTERT expression. D: Kaplan-Meier Event-Free Survival curve for long/normal TL and hTERT expression. E: Kaplan-Meier Event-Free Survival curve for short TL and hTERT expression.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4480695&req=5

Figure 3: A: ALT positive NB cells showing ALT-associated bright intra-nuclear foci of telomere FISH signals (red) (arrows)Nuclear DNA was counterstained with DAPI (blue). B: Immunofluorescence nuclear labeling for the catalytic subunit of telomerase hTERT (green). C: Variance analysis of TL in relation to presence or absence of ALT and to high or low hTERT expression. D: Kaplan-Meier Event-Free Survival curve for long/normal TL and hTERT expression. E: Kaplan-Meier Event-Free Survival curve for short TL and hTERT expression.
Mentions: Telomere elongation is operated by telomerase and ALT mechanism, that is based on recombination of telomeric sequences and might cause heterogeneous TL in single cancer cells [10-12]. ALT was detected by FISH analysis [37-39] in 60/102 NB samples tested; one representative experiment is shown in Fig 3A. Sixteen out of 32 (50%) tumors with heterogeneous TL and 44/70 (62.9%) tumors with homogeneous TL were ALT positive (P=0.22). Variable expression of hTERT was detected by immunofluorescence in 99/102 (97%) NB specimens tested (Fig 3B). Thirty-one out of 99 (31.3%) tumors displayed high hTERT expression [(>0.398 units of fluorescence intensity (FI) while 68/99 (68.7%) showed low hTERT expression (≤0.398 FI). Twenty of 31 cases with high hTERT expression (64.5%) and 40/68 with low hTERT expression (58.8%) were ALT positive, indicating lack of correlation between ALT mechanism and hTERT expression levels (P=0.59).

Bottom Line: Neither ALT-mechanism nor hTERT expression correlated with heterogeneous TL. 3) High hTERT expression and ALT positivity were associated with significantly reduced Overall Survival. 4) High hTERT expression predicted relapse irrespective of patient age.Intratumoral diversity in TL represents a novel feature in NB.In conclusion, diversity of TL in individual NB tumors was strongly associated with disease progression and death, suggesting that these findings are of translational relevance.The combination of high hTERT expression and ALT positivity may represent a novel biomarker of poor prognosis that deserves further investigation.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio di Oncologia, Istituto Giannina Gaslini, Genova, Italy.

ABSTRACT
The purpose of the work was to investigate telomere length (TL) and mechanisms involved in TL maintenance in individual neuroblastoma (NB) tumors. Primary NB tumors from 102 patients, ninety Italian and twelve Spanish, diagnosed from 2000 to 2008 were studied. TL was investigated by quantitative fluorescence in situ hybridization (IQ-FISH) that allows to analyze individual cells in paraffin-embedded tissues. Fluorescence intensity of chromosome 2 centromere was used as internal control to normalize TL values to ploidy. Human telomerase reverse transcriptase (hTERT) expression was detected by immunofluorescence in 99/102 NB specimens.The main findings are the following: 1) two intratumoral subpopulations of cancer cells displaying telomeres of different length were identified in 32/102 tumors belonging to all stages. 2) hTERT expression was detected in 99/102 tumors, of which 31 displayed high expression and 68 low expression. Alternative lengthening of telomeres (ALT)-mechanism was present in 60/102 tumors, 20 of which showed high hTERT expression. Neither ALT-mechanism nor hTERT expression correlated with heterogeneous TL. 3) High hTERT expression and ALT positivity were associated with significantly reduced Overall Survival. 4) High hTERT expression predicted relapse irrespective of patient age. Intratumoral diversity in TL represents a novel feature in NB.In conclusion, diversity of TL in individual NB tumors was strongly associated with disease progression and death, suggesting that these findings are of translational relevance. The combination of high hTERT expression and ALT positivity may represent a novel biomarker of poor prognosis that deserves further investigation.

No MeSH data available.


Related in: MedlinePlus