Chromosome instability, a genetic condition inducing a large number of genetic and chromosome alterations, is a shared feature of most cancers. Using a molecular approach, recent studies on the telomere–telomerase complex in the peripheral blood of patients with familial papillary thyroid cancer (FPTC) have shown the presence of short telomeres and hTERT gene amplification and expression. To study the phenomenon at the chromosomal level, we investigated the presence of chromosome breakage, telomeric association (TA) and telomeric fusion (TF) in phytohemagglutinin-Mstimulated lymphocytes from FPTC patients, unaffected family members (UFM) and healthy subjects (HS). T lymphocyte cultures were obtained from peripheral blood of 13 FPTC patients, 6 UFM and 10 HS. Spontaneous chromosomal instability was evaluated by scoring for TA and chromosomal breakage (gaps, breaks, centric fissions, acrocentric fragments, rings, min/dmin) Giemsa-stained metaphases (200/sample), whereas TF was studied on PNA-telomeric probe (QFISH) hybridized metaphases (50/sample). Q-FISH also allowed measuring the telomere length. Duplication/ amplification of the hTERT gene was investigated by fluorescence in situ hybridization (FISH). FPTC patients displayed increased spontaneous chromosome instability, both with conventional (p=0.045) and molecular (p=0.026) cytogenetic analysis as compared with the other categories. FPTC patients showed a higher frequency of telomeric association than UFM (p=0.00034). Q-FISH analysis revealed that FPTC patients have shorter telomeres (dark telomeres, p= 0.015) as compared with other groups and have a significantly increased number of non-acrocentric (p= 0.039) and acrocentric fusions (p=0.04) and acentric fragments with double telomeric signal (p=0.005) as compared with HS. A few cells from FPTC patients showed three copies of the hTERT gene as compared with UFM and HS cells; however, the result was not statistically significant. Our data confirm the presence of short telomeres in cells from FPTC patients and demonstrate that this phenomenon favours elevated chromosome instability, including telomeric fusion.
Telomeric fusions and chromosome instability in familial papillary thyroid cancer patients
FRAU, DANIELA VIRGINIA;CARIA, PAOLA;VANNI, ROBERTA
2011-01-01
Abstract
Chromosome instability, a genetic condition inducing a large number of genetic and chromosome alterations, is a shared feature of most cancers. Using a molecular approach, recent studies on the telomere–telomerase complex in the peripheral blood of patients with familial papillary thyroid cancer (FPTC) have shown the presence of short telomeres and hTERT gene amplification and expression. To study the phenomenon at the chromosomal level, we investigated the presence of chromosome breakage, telomeric association (TA) and telomeric fusion (TF) in phytohemagglutinin-Mstimulated lymphocytes from FPTC patients, unaffected family members (UFM) and healthy subjects (HS). T lymphocyte cultures were obtained from peripheral blood of 13 FPTC patients, 6 UFM and 10 HS. Spontaneous chromosomal instability was evaluated by scoring for TA and chromosomal breakage (gaps, breaks, centric fissions, acrocentric fragments, rings, min/dmin) Giemsa-stained metaphases (200/sample), whereas TF was studied on PNA-telomeric probe (QFISH) hybridized metaphases (50/sample). Q-FISH also allowed measuring the telomere length. Duplication/ amplification of the hTERT gene was investigated by fluorescence in situ hybridization (FISH). FPTC patients displayed increased spontaneous chromosome instability, both with conventional (p=0.045) and molecular (p=0.026) cytogenetic analysis as compared with the other categories. FPTC patients showed a higher frequency of telomeric association than UFM (p=0.00034). Q-FISH analysis revealed that FPTC patients have shorter telomeres (dark telomeres, p= 0.015) as compared with other groups and have a significantly increased number of non-acrocentric (p= 0.039) and acrocentric fusions (p=0.04) and acentric fragments with double telomeric signal (p=0.005) as compared with HS. A few cells from FPTC patients showed three copies of the hTERT gene as compared with UFM and HS cells; however, the result was not statistically significant. Our data confirm the presence of short telomeres in cells from FPTC patients and demonstrate that this phenomenon favours elevated chromosome instability, including telomeric fusion.File | Dimensione | Formato | |
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