Impact of EGFR and EGFR ligand expression on treatment response in patients with metastatic colorectal cancer

Up to 50% of patients with colorectal cancer (CRC) have either synchronous or metachronous hepatic metastases in the course of their disease. Patients with metastatic CRC (mCRC) whose tumors express wild-type KRAS benefit from treatment with monoclonal antibodies (such as cetuximab or panitumumab) that target the epidermal growth factor receptor (EGFR). However, the therapeutic response to these antibodies is variable, and further predictive models are required. The present study examined whether expression of different EGFRs or their ligands in tumors was associated with the response to cetuximab treatment. Tumor tissues, collected during liver resection in 28 patients with mCRC, were analyzed. The protein expression levels of EGFR/ErbB1, ErbB2, ErbB3 and the EGFR ligands heregulin and amphiregulin were determined using Luminex 200^® and enzyme-linked immunosorbent assays. Computed tomography or magnetic resonance imaging was performed 4 weeks before and 6-8 weeks after treatment with cetuximab. Response to treatment was assessed using the response evaluation criteria for solid tumors (RECIST). The association between the protein expression levels of different EGFRs and their ligands with RECIST criteria was then analyzed to determine whether these protein levels could predict the treatment response to cetuximab. A total of 12 patients exhibited a partial response, 9 exhibited stable disease and 7 exhibited progressive disease after cetuximab therapy according to RECIST. The expression levels of EGFRs (EGFR/ErbB1, ErbB2 and ErbB3) and their ligands (heregulin and amphiregulin) were not significantly associated with the response to cetuximab therapy. Therefore, the present study indicated that EGFR or EGFR ligand expression did not predict treatment response in patients with CRC with liver metastases following cetuximab therapy.

EGFR and EGFR ligands in serum in healthy women; reference intervals and age dependency

Background The epidermal growth factor receptor (EGFR) system is involved in cancer pathogenesis and serves as an important target for multiple cancer treatments. EGFR and its ligands epidermal growth factor (EGF), heparin-binding epidermal growth factor (HB-EGF), betacellulin (BTC), amphiregulin (AREG) and transforming growth factor α (TGF-α) have potential applications as prognostic or predictive serological biomarkers in cancer. The aim was to establish EGFR and EGFR ligand reference intervals in healthy women. Methods EGFR and EGFR ligands were measured in serum from 419 healthy women aged 26-78 years. The need for age partitioned reference intervals was evaluated using Lahti's method. EGFR and EGF were analyzed using ELISA assays, whereas HB-EGF, BTC, AREG and TGF-α were analyzed using the highly sensitive automated single molecule array (Simoa) enabling detection below the lower reference limit for all six biomarkers. Results Reference intervals for EGFR and the EGFR ligands were determined as the 2.5th and 97.5th percentiles. All six biomarkers were detectable in all serum samples. For EGFR, EGF, HB-EGF and TGF-α, reference intervals were established for women <55 years and for women >55 years, whilst common reference intervals were established for AREG and BTC including women aged 26-78 years. Conclusions Age specific reference intervals were determined for EGFR, EGF, HB-EGF, BTC, AREG and TGF-α.

Prognostic and predictive value of EGFR and EGFR-ligands in blood of breast cancer patients: a systematic review

Epidermal growth factor receptor (EGFR) serves as a co-target for dual/pan-EGFR-inhibitors in breast cancer. Findings suggest that EGFR and EGFR-ligands are involved in resistance towards certain breast cancer treatments. The aim is to explore the validity of EGFR and EGFR-ligands in blood as prognostic and predictive biomarkers in breast cancer. The systematic review was conducted in accordance to the PRISMA guidelines. Literature searches were conducted to identify publications exploring correlations between EGFR/EGFR-ligands in serum/plasma of breast cancer patients and prognostic/predictive outcome measures. Sixteen publications were eligible for inclusion. Twelve studies evaluated EGFR, whereas five studies evaluated one or more of the EGFR-ligands. Current evidence indicates associations between low baseline serum-EGFR and shorter survival or reduced response to treatment in patients with advanced breast cancer, especially in patients with estrogen and/or progesterone receptor positive tumors. The prognostic and predictive value of EGFR and EGFR-ligands in blood has only been investigated in highly selected subsets of breast cancer patients and most studies were small. This is the first systematic review evaluating the utility of EGFR and EGFR-ligands as predictive and prognostic biomarkers in blood in breast cancer. Further exploration in large well-designed studies is needed.