Table 2 – mTOR expression profile in cancer
From: Expression of mTOR in normal and pathological conditions
Cancer | mTOR Expression Level | Ref. |
|---|---|---|
Lung | Meta-analysis demonstrated that there is no association between mTOR and p-mTOR expression and the prognosis of non-small cell lung cancer. | [113] |
In EGFR-mutant NSCLC samples mTOR expression was: low or intermediate in 62.5% of the cases and high 37.5%. The group with high mTOR and BIM expression had shorter overall and progression-free survival to erlotinib. | [114] | |
Gastric | Gastroenteropancreatic neuroendocrine tumours presented high levels of mTOR, 4EBP1, p-4EBP1, p-S6K and p-eIF4E. Both expression and activity of mTOR were higher in foregut than in midgut tumours. In foregut tumours, expression of mTOR was higher when distant metastases were present. | [115] |
Immunohistochemistry of paraffinembedded sections from gastric cancer cases reveled that mTOR expression was present in 51.5% (17/33) of the samples, in opposition to the low/absent expression in normal tissues. A positive correlation was observed between mTOR expression and tumor differentiation, lymph node metastasis and clinical staging. No correlation was observed with gender, age and invasive depth. | [116] | |
Higher expression of mTOR and p-mTOR in the tumor center compared to the invasive front. | [117] | |
Liver | Expression of mTOR was elevated in patients with multinodular hepatocellular carcinoma and increased phospho-mTOR in tumoral tissue was associated with higher hepatocellular carcinoma recurrence rates after liver transplantation. | [118] |
Esophageal | PI3K/Akt/mTOR signaling hyperactivation was accompanied with overexpression of mTOR. Expression of mTOR was elevated in tumor tissues in opposition to normal samples. High expression of mTOR and other mTOR signaling components were closely related to higher tumor size, lymph nodes metastases and advanced TNM stage. Overexpression of mTOR was proved to be an independent adverse prognostic factor for overall survival. | [119] |
Laryngeal carcinoma | Expression of mTOR ranged from 0.0–80.2% and higher expression of mTOR was associated with increased recurrence and shorter disease-free survival. | [120] |
Expression of mTOR was higher in patients with disease recurrence and was associated with shorter disease-free survival. | [121] | |
Urothelial carcinoma | mTOR protein levels were elevated in tumours of urothelial patients that did not respond to neoadjuvant chemotherapy and decreased in complete responders. | [122] |
Pancreatic | Expression of mTOR observed in about 71% of cases and correlated with p-mTOR expression. Patients with positive p-mTOR expression seemed to have shorter survival duration. | [123] |
Breast | From the analysed luminal breast cancer specimens, 43.8% were positive for p-mTOR and a correlation between p-mTOR expression and smaller and lower-grade tumors was observed. | [124] |
Prostate | Protein levels of mTOR are double in cancer tissue compared to normal and with a diffuse distribution, whereas p-mTOR localized in the cytoplasm, and presented a more focal expression (being also elevated in cancer and prostate intraepithelial neoplasia cells) | [125] |
Ovarian | Expression of mTOR was up-regulated in PEO1TaxR (paclitaxel-resistant) ovarian cancer cells when compared with paclitaxel-sensitive PEO1 cells; and downregulated in SKOV-3TaxR (paclitaxel-resistant) cells when compared with the parental cellular counterparts. | [126] |
Expression of mTOR was increased in endometriosis and ovarian endometrioid adenocarcinoma patients compared to normal samples. | [127] | |
Leukemia | Expression of mTOR and p-mTOR was associated higher risk of paediatric acute lymphoblastic leukaemia (ALL) relapse. | [128] |
Expression of mTOR was upregulated in more than 50% of cases of ALL, both T- or B-ALL, and it was observed that the mean fold change of mTOR expression was higher in patients that did not respond to chemotherapy. | [53] | |
Multiple Myeloma | Expression of mTOR or p-mTOR was observed in 25.8% FFPE samples from MM patients and high mTOR and p-mTOR were associated with male gender and older patients. | [129] |
Sacral chordoma | Expression of mTOR observed in 62.5% (25/40) cases of the sacral chordoma and it was associated with tumor invasion into the surrounding muscles. | [130] |