Purpose: Recently, activating mutations of the epidermal growth factor receptor (EGFR) gene were discovered in non-small cell lung cancers sensitive to gefitinib (ZD1839, an EGFR tyrosine kinase inhibitor) but not in gefitinib-resistant cancers. Abnormalities of EGFR and related pathways may have an effect on responsiveness of advanced colorectal cancer to combination chemotherapy with gefitinib.

Experimental Design: We examined patients with previously untreated metastatic colorectal cancer, who were enrolled into two phase I/II trials of combination chemotherapy (irinotecan, leucovorin, and 5-fluorouracil) and daily oral gefitinib. We obtained paraffin tissue blocks of primary tumors from 31 patients, sequenced the EGFR, KRAS, and BRAF genes, and did immunohistochemistry for EGFR, phosphorylated AKT1, p53, p21, and p27.

Results: Twelve (39%) of the 31 patients experienced a partial objective response to the therapy. A novel EGFR mutation in exon 18 (c.2170G>A, p.Gly724Ser) was identified in only one patient who did not experience an objective tumor response. EGFR immunohistochemistry was not predictive of responsiveness. In contrast, loss of p21 was associated with a higher response rate to therapy (P = 0.05). Moreover, the response rate among patients whose tumors maintained p21 expression and possessed a mutation in p53 was only 9% (1 of 11, P = 0.005). Overexpression of phosphorylated AKT1 also seemed to predict a trend towards resistance to the therapy.

Conclusions: p21 expression in colorectal cancer, especially in combination with p53 mutation, is a predictor of resistance to the combination chemotherapy with gefitinib. Activating EGFR mutations are rare in colorectal cancer and do not seem to confer sensitivity to gefitinib and chemotherapy.

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-05-0738DOI Listing

Publication Analysis

Top Keywords

colorectal cancer
20
combination chemotherapy
16
chemotherapy gefitinib
8
advanced colorectal
8
egfr
8
cancer combination
8
phosphorylated akt1
8
response rate
8
p21 expression
8
response
5

Similar Publications

Cytosolic DNA composition is determined by genomic instability mechanism and regulates dendritic cell-mediated anti-tumor immunity.

Cell Rep

January 2025

Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, AB T6G 1Z2, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2R3, Canada. Electronic address:

Patients with colorectal cancers (CRCs) that have microsatellite instability (MSI) (MSI CRCs) face a better prognosis than those with the more common chromosomal instability (CIN) subtype (CIN CRCs) due to improved T cell-mediated anti-tumor immune responses. Previous investigations identified the cytosolic DNA (cyDNA) sensor STING as necessary for chemokine-mediated T cell recruitment in MSI CRCs. Here, we find that cyDNA from MSI CRC cells is inherently more capable of inducing STING activation and improves cytotoxic T cell activation by dendritic cells (DCs).

View Article and Find Full Text PDF

Background: Gastric cancer peritoneal metastasis lacks effective predictive indices. This article retrospectively explored predictive values of DNA ploidy, stroma, and nucleotyping in gastric cancer peritoneal metastasis.

Methods: A comprehensive analysis was conducted on specimens obtained from 80 gastric cancer patients who underwent gastric resection at the Department of Gastrointestinal Surgery of Wuhan University Renmin Hospital.

View Article and Find Full Text PDF

Encorafenib + cetuximab (EC) is approved for previously treated BRAF V600E-mutant metastatic colorectal cancer (mCRC) based on the BEACON phase 3 study. Historically, first-line treatment of BRAF V600E-mutant mCRC with chemotherapy regimens has had limited efficacy. The phase 3 BREAKWATER study investigated EC+mFOLFOX6 versus standard of care (SOC) in patients with previously untreated BRAF V600E mCRC.

View Article and Find Full Text PDF

Hereditary colorectal cancer syndromes and inflammatory bowel disease: results from a registry-based study.

Int J Colorectal Dis

January 2025

Hereditary Digestive Tract Tumors Unit, Fondazione IRCCS Istituto Nazionale Dei Tumori, Via Giacomo Venezian 1, 20133, Milan, Italy.

Purpose: In this study, we investigated the progression of high-grade dysplasia (HGD)/CRC in patients with hereditary colorectal cancer syndromes (HCSS) and concomitant inflammatory bowel diseases (IBDs).

Methods: We described the natural history of a series of patients with confirmed diagnosis of hereditary colorectal cancer syndromes (HCCSs) and concomitant IBDs who were referred to the Hereditary Digestive Tumors Registry at the Fondazione IRCCS Istituto Nazionale dei Tumori of Milan.

Results: Between January 1989 and April 2024, among 450 patients with APC-associated polyposis and 1050 patients with Lynch syndrome (LS), we identified six patients with IBDs (five with UC, one with ileal penetrating CD) and concomitant HCCSs (five with LS, one with APC-associated polyposis).

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!