Luca Emanuele Pollina

MicroRNA-21 (miR-21) was reported to be overexpressed and contributes to invasion and gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to evaluate whether miR-21 expression was associated with the overall survival (OS) of PDAC patients treated with gemcitabine and to provide mechanistic insights for new therapeutic targets. miR-21 expression was evaluated in cells (including 7 PDAC cell lines, 7 primary cultures, fibroblasts, and a normal pancreatic ductal cell line) and tissues (neoplastic specimens from 81 PDAC patients and normal ductal samples) isolated by laser microdissection. The role of miR-21 on the pharmacologic effects of gemcitabine was studied with a specific miR-21 precursor (pre-miR-21). Patients with high miR-21 expression had a significantly shorter OS both in the metastatic and in the adjuvant setting. Multivariate analysis confirmed the prognostic significance of miR-21. miR-21 expression in primary cultures correlated with expression in their respective tissues and with gemcitabine resistance. Pre-miR-21 transfection significantly decreased antiproliferative effects and apoptosis induction by gemcitabine, whereas matrix metalloproteinase (MMP)-2/MMP-9 and vascular endothelial growth factor expression were upregulated. Addition of inhibitors of phosphoinositide 3-kinase and mammalian target of rapamycin resulted in decrease of phospho-Akt and prevented pre-miR-21-induced resistance to the proapoptotic effects of gemcitabine. miR-21 expression correlated with outcome in PDAC patients treated with gemcitabine. Modulation of apoptosis, Akt phosphorylation, and expression of genes involved in invasive behavior may contribute to the role of miR-21 in gemcitabine chemoresistance and to the rational development of new targeted combinations.

PURPOSE: PTEN, AKT, and KRAS are epidermal growth factor receptor (EGFR) downstream regulators. KRAS mutations confer resistance to cetuximab. This retrospective study investigated the role of PTEN loss, AKT phosphorylation, and KRAS mutations on the activity of cetuximab plus irinotecan in patients with metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: A cohort of patients with irinotecan-refractory mCRC who were treated with cetuximab plus irinotecan was tested for PTEN immunoreactivity (ie, immunohistochemistry; IHC), pAKT IHC, and KRAS mutations. Analyses were performed both on primary tumors and on related metastases, and the association among IHC, mutational results, and treatment outcomes was investigated. RESULTS: One-hundred two patients were eligible. Ninety-six primary tumors, 59 metastases, and 53 paired samples were available. Forty-nine primary tumors (58% of assessable samples) had a preserved PTEN expression (PTEN-positive), whereas 35 (40% of assessable samples) were pAKT-positive. Levels of concordance between primary tumors and metastases were 60%, 68%, and 95% for PTEN, pAKT, and KRAS, respectively. PTEN status on primary tumors and pAKT status both on primary tumors and on metastases did not predict response or progression-free survival (PFS). On metastases, 12 (36%) of 33 patients with PTEN-positive tumors were responders compared with one (5%) of 22 who had PTEN-negative tumors (P = .007). The median PFS of patients with PTEN-positive metastases was 4.7 months compared with 3.3 months for those with PTEN-negative metastases (hazard ratio [HR], 0.49; P = .005). Patients with PTEN-positive metastases and KRAS wild type had longer PFS compared with other patients (5.5 months v 3.8 months; HR, 0.42; P = .001). CONCLUSION: PTEN loss in metastases may be predictive of resistance to cetuximab plus irinotecan. The combination of PTEN IHC and KRAS mutational analyses could help to identify a subgroup of patients with mCRC who have higher chances of benefiting from EGFR inhibition.

In Brief Objective/Background: The GONO-FOLFOXIRI regimen improved the rate of R0 secondary resection of metastases in initially unresectable metastatic colorectal cancer. The objective of this study was to evaluate the long-term outcome of resected patients and the impact of FOLFOXIRI on perioperative morbidities, mortality, and chemotherapy induced hepatotoxicity. Patients and Methods: Overall, 196 patients with initially unresectable metastatic colorectal cancer were treated with FOLFOXIRI in 2 phase II and 1 phase III trial. This regimen was associated with an elevated response rate (70.4%) and 37 patients (19%) could undergo a secondary R0 surgery on metastases. This study was registered with the Australian New Zealand Clinical Trials Registry Database at http://www.anzctr.org.au/Statistics.aspx and has ID number ACTRN12608000615381. Results: Main characteristics of the 37 radically resected patients were: median age 64 years (45–73), Eastern Cooperative Oncology Group Performance Status (ECOG) PS ≥1 in 30%, synchronous metastases in 65%, multiple sites of disease in 22%, and metastases confined to the liver in 68%. Preoperative FOLFOXIRI was administered for a median of 5.5 months. There was no perioperative mortality and all morbidities (27% of patients) resolved without sequelae. After a median follow up of 67 months, 5-year and 8-year survival are 42% and 33% respectively. At 5 years, 29% of patients are free of disease. The analysis of treatment-induced liver injury showed neither G3 vascular toxicity nor G4 steatosis, and steato-hepatitis in only 5% of patients. Conclusions: The GONO-FOLFOXIRI regimen allow an R0 surgery in approximately 1 out of 5 unselected patients with initially unresectable metastatic colorectal cancer, and the long-term survival of resected patients is considerable. Neoadjuvant FOLFOXIRI for 3-6 months is safe and not associated with severe liver injury. We evaluated 196 patients with initially unresectable metastatic colorectal cancer treated with the triple drug combination FOLFOXIRI. This regimen allowed an R0 surgery in approximately 1/5 patients, and the long-term outcome of resected patients is considerable (8-year survival 33%). Neoadjuvant FOLFOXIRI for 3–6 months is safe and not associated with severe liver injury.

Codon 61 of the N-ras oncogene was screened for mutations in 99 surgically resected thyroid carcinomas by a polymerase chain resection (PCR)-based method (PCR-primer introduced restriction with enrichment of mutant alleles [PCR-PIREMA]). A point mutation of the N-ras oncogene at the codon 61 was detected in 16 of 99 (16.2%) thyroid carcinomas examined by this method. No RAS alteration was detected in the group of 11 medullary thyroid carcinomas, while 3 of 31 (10.0%) papillary carcinomas, 2 of 5 (40%) follicular carcinomas, 8 of 44 (18.2%) poorly differentiated carcinomas, and 3 of 5 (60%) undifferentiated carcinomas showed an activation of N-RAS proto-oncogene. Interestingly, two primary follicular tumors and their corresponding bone metastases, showed N-ras mutations. In the same cases we evaluated the expression of thyroglobulin by immunohistochemical analysis. Although the majority of well-differentiated carcinomas expressed a high level of thyroglobulin, the expression of the same antigen was absent or only occasional weakly positive in 33 of 44 poorly differentiated carcinomas. Interestingly, N-ras mutation was restricted to the group of tumours with low or absent thyroglobulin expression, suggesting that this genetic change is prevalent in less differentiated tumors.