Combined Analysis of EGFR and PTEN Status in Patients With KRAS Wild-Type Metastatic Colorectal Cancer

New Perspectives in Colorectal Cancers Treatment, the Role of MicroRNAs

The main epidemiological and clinical data on colorectal cancer, as well as the features of molecular pathology, are discussed in the literature review. Efforts are being putto identify promising targets, particularly small non-coding nucleotide sequences, which can lead to new treatments for this disease. The discovery of significant mutations that contribute to the development of colorectal tumors is a major step in the advancement of molecular oncology, as these mutations give rise to heterogeneous tumors that differ in their origin. These mutations play a significant role in the progression of the disease and are now being targeted for treatment. The prognosis for a disease is influenced by the patient's sensitivity to antitumor therapy. However, new approaches to finding effective targets for antitumor treatments face new fundamental challenges due to clinical issues. These issues include the epigenetic regulation of markers of oncogenesis, which allows for the development of new therapeutic strategies. RNA interference, in particular, has been linked to non-copying RNA sequences such as microRNAs. These microRNAs are associated with certain processes that can influence all aspects of oncogenesis. The diversity of microRNAs allows for a differentiated approach when treating tumors in various locations.

Evaluating the value of Amphiregulin, Phosphatase and Tensin Homologue (PTEN) and P21 Expression for Anti-EGFR Treatment in Metastatic Colorectal Carcinoma

BACKGROUND

Despite the significant progress in target therapy for the treatment of metastatic colorectal carcinoma (mCRC), the overall survival isn't satisfactory.

METHODS

We assessed the expression of Amphiregulin, PTEN, and P21 in sections from 23 paraffin blocks prepared from 23 patients with left-sided mCRC using immunohistochemistry (IHC). The relationship between their level of expressions, clinicopathological parameters, response to anti-EGFR, and prognosis were analyzed.

RESULTS

High Amphiregulin, PTEN and low P21 expression levels were associated with low tumor grade (p= 0.038 and 0.025 respectively), better response to anti-EGFR treatment (p <0.001), and favorable outcome {progression-free survival (PFS) and overall survival (OS)} (p <0.05). There was a direct relation between Amphiregulin and PTEN expressions (phi coefficient=+0.840), while there was an inverse relation between P21expression and both Amphiregulin (phi coefficient= -0.840) and PTEN expressions (phi coefficient = -1.000), which was statistically significant (P <0.001).

CONCLUSION

High Amphiregulin and PTEN expression levels and low P21 expression levels were associated with better response to anti-EGFR therapy and improved survival outcome. They might be considered predictive markers of response to anti-EGFR therapy in mCRC.<br /> <br />.

Oncologic Outcomes in Metastatic Colorectal Cancer with Regorafenib with FOLFIRI as a Third- or Fourth-Line Setting

BACKGROUND

To evaluate the efficacy and toxicities of regorafenib plus irinotecan, dose-escalated on the basis of uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotyping, in previously heavily treated metastatic colorectal cancer (mCRC) and the prognostic values of EGFR expression, KRAS mutations, and tumor sidedness.

METHODS

Forty-one patients with mCRC with disease progression after treatment with fluoropyrimidines, oxaliplatin, irinotecan, anti-VEGF, and anti-EGFR MoAbs were subjected to UGT1A1 genotyping and received regorafenib combined with FOLFIRI with dose-escalated irinotecan.

RESULTS

The median follow-up period was 10.0 months (1.3-23.5 months). The overall disease control rate was 58.5%, whereas the median progression-free survival (PFS) and overall survival (OS) were 6.0 months and 12.0 months, respectively. KRAS mutations were significantly associated with positive EGFR expression (P = .026). KRAS mutations significantly correlated with a shorter OS than KRAS wild-type (6.0 vs. 14.4 months, P = .014) but had no significant association with PFS. Positive EGFR expression had an inverse correlation with PFS (2.5 vs. 14.0 months, P = .039) and OS (9.6 vs. 19.7 months, P = .044). Moreover, left-sided tumors associated with superior PFS (2.0 vs. 7.0 months, P < .0001) and OS (4.0 vs. 13.0 months, P < .0001), and tumor sidedness was an independent prognostic factor by the multivariate analysis.

CONCLUSION

Regorafenib and FOLFIRI concomitant therapy with dose-escalated irinotecan seemed to be potentially practicable with satisfactory oncological results. KRAS mutations and EGFR expression might be predictors of poor oncological outcomes; however, left-sided mCRCs would be more beneficial for concomitant regorafenib and FOLFIRI therapy.

The interference between oxaliplatin & anti-EGFR therapies: a different hypothesis to explain the 'unexplainable'

This paper has been written because we have a differing idea concerning the suspected negative interference between oxaliplatin and anti-EGFR therapies in cancer patients. Several multicenter, randomized, controlled clinical trials investigated whether the efficacy of oxaliplatin-based chemotherapy is improved by the addition of anti-EGFR therapies in patients affected by KRAS wild-type advanced colorectal cancer. Results of these trials have produced puzzling findings, with some studies demonstrating improved survival and other studies showing no differences in overall survival between experimental and control arms. Moreover, a detrimental effect has been demonstrated in some settings. Nevertheless, the extent of this interaction remains uncertain. Some physicians proposed personal interpretations. This paper describes our hypothesis.

Involvement of microRNA-141-3p in 5-fluorouracil and oxaliplatin chemo-resistance in esophageal cancer cells via regulation of PTEN

microRNAs (miRNAs) act as a major regulator of acquired chemo-resistance in various types of cancer therapeutics. This study investigated the contribution of miRNAs in influencing multiple drug resistance in esophageal squamous cell carcinoma (ESCC). The sensitivity of four ESCC cell lines (EC109, EC9706, TE-1 and KYSE-150) to 5-fluorouracil (5-FU) and oxaliplatin (OX) was determined by MTT assay. A 5-FU and OX-resistant subline, EC9706R, was established by continuous exposure to stepwise increasing concentration of 5-FU and OX. Microarray technology was used to compare the differential expression of miRNAs between resistant cells and parental cells. Chemo-sensitivity assay was performed to evaluate drug response in EC9706R cells transfected with miRNA mimic or inhibitor. The direct targets of miRNA were identified by employing pathway analysis and then confirmed with luciferase assay. Sixty ESCC tissue samples and their paired adjacent normal tissues were collected to validate the expression of identified miRNA. Mouse models were further utilized to investigate the function of miRNA on acquired chemo-resistance. MicroRNA panel results indicated that a total of 12 miRNAs were differentially expressed and miR-141-3p was highly over expressed in resistant cells. Inhibition of miR-141-3p reversed acquired chemo-resistance in EC9706R cells by stimulating apoptosis. The expression of miR-141-3p was significantly increased in ESCC tissue samples compared to their matched distant normal tissues. In addition, the elevated miR-141-3p expression was found to be associated with ESCC differentiation status and TNM stage. Moreover, Phosphatase and tensin homolog (PTEN) was identified as direct target of miR-141-3p. Western blot exhibited altered protein levels of PTEN, Akt, and PI3k with miR-141-3p inhibitor. An inverse correlation between PTEN expression and miR-141-3p expression was also observed in tissue samples. EC9706R xenograft mouse model became sensitized to 5-FU and OX treatment following miR-141-3p inhibitor transfection in vivo. Our study demonstrated that miR-141-3p contributed to an acquired chemo-resistance through PTEN modulation both in vitro and in vivo.