Table 2.
Increased TERC copy number in cancer
| Human cancer type | Number and types of samples | Method of TERC copy number analysis | Definition for TERC gain or amplificaton | Result | References |
|---|---|---|---|---|---|
| Cervix, Head & neck, lung cancer | 33 cervical carcinomas (32 squamous and one adenocarcinoma), 31 head and neck carcinomas (30 squamous, one adenocarcinoma), 9 lung carcinomas (squamous non‐small cell) | FISH probed with a P1 clone containing TERC sequence (interphase) | Amplification definition: >10 TERC hybridization signals per nucleus, high density of signals | TERC Amplification: 4/73 (5%) (2/33 cervix, 1/31 head and neck, 1/9 lung) | ( 19 ) |
| TERC gain definition: TERC signal >2 per cell in >10% of the cells | TERC gain: 29/30 (97%) of tumors investigated | ||||
| Cervix, ovary and lung cancer | 9 ovarian tumor samples, 8 cervical carcinoma cell lines, 7 SCLC cell lines, 1 ovarian carcinoma cell line, 3 NSCLC cell lines, | Southern: used 17 probes spaning 3q including two probes within TERC gene | Not defined | • More than 2 copies of TERC gene: | ( 24 ) |
| FISH: used two 3q26 specific probes | 7/8 ovarian tumor samples, | ||||
| 3/8 cervical carcinoma cell lines, | |||||
| 5/7 SCLC cell lines. | |||||
| • 5/8 (62%) ovarian tumor had more than 4 copies of TERC gene | |||||
| • Increased copy number peaked at 3q26 in the 8 cervical carcinoma cell lines, the 7 SCLC cell lines and the 9 ovarian tumors | |||||
| Melanomas | 48 primary cell cultures from 46 CMM patients | FISH: using a BAC clone containing the TERC locus | Not defined | Frequencies not given, but increase in copy number of chromosome region detected by CGH in 16/50 cell lines | ( 32 ) |
| One culture from a dysplastic naevus | Southern: using primers specific for TERC | ||||
| Melanoma celll line SK‐Mel‐28 | |||||
| Lung cancer | 19 NSCLC cell lines (10 from squamous cell carcinomas and 9 from adenocarcinomas) | FISH using a BAC probe containing TERC gene (metaphase) | Not defined | FISH: 5–16 TERC signals were detected in metaphases of the 5 cell lines examined | ( 37 ) |
| Southern: using a probe containing hTR cDNA sequence | Southern: 47% of the 19 lines showed increased TERC copy number | ||||
| Increased TERC copy number correlates with hTR expression | |||||
| Cervix cancer | 57 thin‐layer cytological specimens | FISH using CEP7, CEP3, and TERC probes | Higher copy numbers of TERC compared to CEP7 | Cells with multiple TERC signals increased with the severity of the cytologic interpretation | ( 40 ) |
| Cervix cancer | 59 pap smears | Same as above | TERC signal >2 per cell in >20% of the cells | increased copy number of TERC was associated with progression of premalignant dysplastic lesions | ( 41 ) |
| Cervix cancer | 12 primary cervical adenocarcinomas | Same as above | Not defined | TERC gain or amplification was found in all cervical adenocarcinomas investigated | ( 39 ) |
| Esophageal carcinomas | 60 primary tumors | qPCR | Not defined | Average TERC copy number: 5.28 (±0.54) | ( 38 ) |
| Leukemia | 29 ALL | FISH using probes for TERC and reference probe of chr3 | Not defined | 2–12 copiesof TERC detected | ( 29 ) |
| 16 ANLL | |||||
| Myeloblastic cell line K562 |
CEP3 and CEP7, probes containing repeat sequences specific for the centromeres of chromosomes 3 (CEP3) and 7 (CEP7);
ALL, acute lympholastic leukemia; ANLL, non‐lymphoblastic leukemia; BAC, bacterial artificial chromosome; CGH, comparative genomic hybridization; CMM, cutaneous malignant melanoma; FISH, fluorescence in situ hybridization; TERC, telomerase RNA component; hTR, human telomerase RNA; NSCLC, non‐small cell lung cancer; qPCR, quantitative polymerase chain reaction; SCLC, small cell lung cancer.