Table 1.
In vivo expression of different IGF1 isoforms (mRNA, protein) in selected human cancers.
| Human Cancer | Tissue Material/Technique | IGF1 mRNAs | IGF1 Propeptides/Peptides | No of ref. | ||||
|---|---|---|---|---|---|---|---|---|
| IGF1Ea (Class I and II) | IGF1Eb (Class I and II) | IGF1Ec (Class I and II) | Pro-Ea/Ea | Pro-Eb/Eb | Pro-Ec/Ec (MGF) | |||
| Brain cancer | n = 9 gliomas; IHC, RT-PCR | (+) | (+) | (-) | nt | [183] | ||
| Colorectal cancer | One colonic and one retro-sigmoidal NENs; IHC | nt | nt | (-) Ec peptide in both CRC | [32] | |||
| n = 13 pairs of CRC/CT; IHC; qRT-PCR | (+) ↑ vs. CT; ↑ vs. Eb&Ec; | (+) ↓ vs. CT; ↑ vs. Ec | (+) ≈ vs. CT | nt | [104] | |||
| ↓ class I/II vs. CT; ↑ class II vs. class I; | ||||||||
| n = 28 pairs of CRC/CT; IHC; qRT-PCR | (+); 82% of all transcripts; ≈ vs. Eb; ↑ vs. Ec | (+); 17% of all transcripts; ↑ vs. Ec | (+); ~1% of all transcripts | nt | [105] | |||
| ↓ all isoforms vs. CT; CRC: Class I - 59%; class II - 41%, in quantitative expression - NS | ||||||||
| CRC/polyps/CT; fluorescent gold nanoparticles | nt | nt | (+) Ec peptide (MGF); in C | [34] | ||||
| Epithelial Cervical cancer | One uterine cervical NEN; IHC | nt | nt | (+) Ec peptide; in C | [32] | |||
| n = 29 squamous CC (HPV+), n = 28 L-SIL (HPV+), n = 30 H-SIL (HPV+), n = 20 CT (HPV-); PCR, qRT-PCR | (+++) 85% in CC; 92% in CT | (+++) 14% in CC; 8% in CT | (+++) 1% in CC and CT | nt | [49] | |||
| Class I - 69–86%; class II - 14–31%; ↑ of all isoforms in pre-cancerous tissues vs. CC and CT, and a shift in the balance towards IGF1Eb in CC; (+) correlation between the FOX2 mRNA expression and Ea/Eb in precancerous and CC, and Ec in L-SIL and H-SIL | ||||||||
| Gastric cancer | n = 8 NENs; IHC | nt | nt | (+) Ec peptide in 37.5%; in C | [32] | |||
| Lung cancer | n = 2 NENs; IHC | nt | nt | (+) Ec peptide in one LC; in C | [32] | |||
| Pancreatic cancer | n = 17 NENs; IHC | nt | nt | (+) Ec peptide in 58.8%; in C | [32] | |||
| Prostate cancer | IHC, Western blot, RT-PCR | nt | nt | (+++) MGF; ↑ PC and PIN vs. CT | [108] | |||
| n = 83 patients; paraffin sections; IHC | nt | nt | (+) Ec peptide; in C; #, ↑ Ec peptide | [109] | ||||
| n = 78 patients; IHC; Western blot, qRT-PCR | nt | nt | (+) Ec peptide; #, ↑ Ec peptide | [166] | ||||
| Small intestine cancer | n = 9 NENs, IHC | nt | nt | (+) Ec in 44.4%; in C | [32] | |||
| Thyroid cancer | n = 92 of different types of TC; IHC, qRT-PCR | nt | (+) IGF1Ec; ↑in more aggressive vs. non-aggressive papillary TC | nt | (+) Ec peptide in papillary TC; in C; #, ↑ Ec | [35] | ||
| Urinary bladder cancer | n = 46 biopsies/CT; qRT-PCR | (+) marginally ↑ vs. CT | (+) marginally ↑ vs. CT | ↓ vs. CT; #, ↓IGF1Ec | nt | nt | [33] | |
| ↑ of all IGF1 mRNA isoforms in in situ carcinomas | ||||||||
| UPO | n = 4 NENs; IHC | nt | nt | (+) Ec peptide in 100%; in C | [32] | |||
| Others | NENs; appendiceal (n = 3), gallbladder (n = 1); IHC | nt | nt | (-) Ec peptide in 100% | [32] | |||
Legend: (+)—positive expression; (+++)—overexpression; (-)—lack of expression; ↑/↓—significant increased/decreased; #—significant correlation with clinical TNM stage, tumor grade, and/or disease recurrence; C—cytoplasm; CC—cervical cancer; CRC—colorectal cancer; CT—control tissue; HPV—Human Papillomavirus; H-SIL—high-grade squamous intraepithelial lesions; IHC—immunohistochemistry; L-SIL—low-grade squamous intraepithelial lesions; MGF—mechano-growth factor; NENs—neuroendocrine neoplasms; NS—non significant; nt—non tested; PC—prostate cancer; PIN—prostatic intraepithelial neoplasia; qRT-PCR—quantitative real-time polymerase chain reaction (PCR); TC—thyroid cancer; UPO—cancers of unknown primary origin.