Analysis of epidermal growth factor receptor expression as a predictive factor for response to gefitinib ('Iressa', ZD1839) in non-small-cell lung cancer

Gefitinib ('Iressa', ZD1839) is an orally active epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated antitumour activity and favourable tolerability in Phase II studies. We investigated whether EGFR expression levels could predict for response to gefitinib in patients with advanced non-small-cell lung cancer (NSCLC), who received gefitinib (250 mg day(-1)) as part of a worldwide compassionate-use programme. Tissue samples were analysed by immunohistochemistry to assess membrane EGFR immunoreactivity. Of 147 patients enrolled in our institution, 50 patients were evaluable for assessment of both clinical response and EGFR expression. The objective tumour response rate was 10% and disease control was achieved in 50% of patients. Although high EGFR expression was more common in squamous-cell carcinomas than adenocarcinomas, all objective responses were observed in patients with adenocarcinoma. Response and disease control with gefitinib were not associated with high EGFR expression. Overall, median survival was 4 months, and the 1-year survival rate was 18%. Strong EGFR staining correlated with shorter survival time for all patients. Gefitinib demonstrated promising clinical activity in this group of patients with NSCLC. These results have also shown that EGFR expression is not a significant predictive factor for response to gefitinib.     

Gefitinib ('Iressa', ZD1839) and new epidermal growth factor receptor inhibitors

The epidermal growth factor receptor (EGFR) is a promising target for cancer therapy and a number of EGFR-targeted agents have been developed. Those most advanced in development are the EGFR tyrosine kinase inhibitors gefitinib ('Iressa', ZD1839) and erlotinib ('Tarceva', OSI-774), and the monoclonal antibody cetuximab ('Erbitux', IMC-C225). This review provides a clinical overview of these agents, highlighting their antitumour activities in different tumour types. Epidermal growth factor receptor-targeted agents are generally well tolerated and are not typically associated with the severe adverse events often seen with cytotoxic chemotherapy. Gefitinib is the agent with the most extensive clinical experience, particularly in non-small-cell lung cancer (NSCLC). Recently, gefitinib became the first-approved EGFR-targeted agent, for use in patients with previously treated advanced NSCLC in Japan, the USA and other countries. Further studies are required to explore the full potential of these novel agents either as monotherapy or combination therapy.     

Activity of a specific inhibitor, gefitinib (Iressa, ZD1839), of epidermal growth factor receptor in refractory non-small-cell lung cancer.

BACKGROUND: Gefitinib (Iressa(TM), ZD1839) is an orally active, selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. Phase I studies showed that it is well tolerated, with evidence of tumor regression in patients with advanced non-small-cell lung cancer (NSCLC). Therefore, we aimed to assess the antitumor activity and tolerability of gefitinib in a series of patients with previously treated, advanced NSCLC, as a part of a compassionate use program. PATIENTS AND METHODS: To be eligible, all patients were required to have histologically or cytologically proven advanced or metastatic NSCLC, prior chemotherapy with at least one cisplatin-containing chemotherapy regimen or contraindication to cytotoxic drugs, Eastern Cooperative Oncology Group performance status < or =2, and adequate hematological, renal and hepatic parameters. All patients provided signed informed consent. Patient re-evaluation was performed every 4-6 weeks. RESULTS: Seventy-three consecutive patients were enrolled. Response rate, including complete and partial response, was 9.6%; an additional 43.8% of patients achieved stable disease, for an overall disease control of 53.4%. EGFR1 status was evaluated by immunocytochemistry in 25 patients. According to EGFR1 immunoreactivity all responses were observed with medium/strong imunoreactivity while three out of four responses were observed in high expressive patients. Median survival for all patients was 4 months while it reached 6 months for patients with disease control. The 1-year survival rate was 13.1% for the entire series and 23.2% for patients with disease control. Non-hematological toxicity was generally mild. CONCLUSION: Gefitinib has promising activity with a good toxicity profile in patients with progressive NSCLC who have received one or two prior chemotherapy regimens. A possible relationship within response and EGFR1 expression is suggested.     

ZD1839 (Iressa), a novel epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, potently inhibits the growth of EGFR-positive cancer cell lines with or without erbB2 overexpression.

Overexpression of the growth factor receptors EGFR and erbB2 occurs frequently in several human cancers and is associated with aggressive tumour behaviour and poor patient prognosis. We have investigated the effects of ZD1839 (Iressa), a novel EGFR tyrosine kinase inhibitor, on the growth, in vitro and in vivo, of human cancer cell lines expressing various levels of EGFR and erbB2. Proliferation of EGFR-overexpressing A431 and MDA-MB-231 cells in vitro was potently inhibited (50%-70%) by ZD1839 with half-maximally effective doses in the low nanomolar range. In parallel, ZD1839 blocked autophosphorylation of EGFR and prevented activation of PLC-gamma 1, ERK MAP kinases and PKB/Akt by EGF. It also inhibited proliferation in EGFR(+) cancer cell lines overexpressing erbB2 (SKBr3, SKOV3, BT474) by between 20% and 80%, effects which correlated with inhibition of EGF-dependent erbB2 phosphorylation and activation of ERK MAP kinase and PKB/Akt in SKOV3 cells. Oral administration of ZD1839 inhibited the growth of MDA-MB-231 and SKOV3 tumours, established as xenografts in athymic mice, by 71% and 32%, respectively. Growth inhibition coincided with reduced proliferation but no change in apoptotic index. Collectively, these results show that ZD1839, at the doses studied, is a potent inhibitor of proliferation not only in cells overexpressing EGFR but also in EGFR(+) cells that overexpress erbB2.     

Efficacy of epidermal growth factor receptor-targeted molecular therapy in anaplastic thyroid cancer cell lines

Anaplastic thyroid cancer is one of the most aggressive human malignancies and the outcomes of conventional therapy have been far from satisfactory. Recently, epidermal growth factor receptor (EGFR)-targeted therapy has been introduced as an alternative therapeutic strategy for highly malignant cancers. This study was undertaken to investigate the expression of EGFR in anaplastic thyroid cancer cell lines, and to explore the potential of therapies targeting EGFR as a new therapeutic approach. EGFR was universally expressed in anaplastic cancer cell lines at a variety of levels. Specific EGFR stimulation with epidermal growth factor showed significant phosphorylation of ERK1/2 and Akt, and resulted in marked growth stimulation in an anaplastic thyroid cancer cell line, which highly expressed EGFR. This EGFR-transmitted proliferation effect of the cancer cell line was completely inhibited by gefitinib, an EGFR tyrosine kinase inhibitor. Moreover, growth of xenografts inoculated in mice was inhibited in a dose-dependent manner with 25-50 mg kg(-1) of gefitinib administrated orally. Inhibition of EGFR-transmitted growth stimulation by gefitinib was clearly observed in anaplastic thyroid cancer cell lines. Our results suggested that EGFR-targeted therapy, such as gefitinib, might be worth further investigation for the treatment of anaplastic thyroid cancer.     

Retracted: Genistein enhances the effect of epidermal growth factor receptor tyrosine kinase inhibitors and inhibits nuclear factor kappa B in nonsmall cell lung cancer cell lines

BACKGROUND:

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) have shown modest clinical benefit in patients with relapsed nonsmall cell lung cancer (NSCLC). Down‐regulation of Akt appears to correlate with the antitumor activity of EGFR‐TKIs. Akt activates nuclear factor kappa B (NF‐κB), which transcribes genes important for cell survival, invasion, and metastasis. The authors hypothesized that genistein, through the inhibition of NF‐κB, could enhance the activity of EGFR‐TKIs in NSCLCs.

METHODS:

Three NSCLC cell lines with various EGFR mutation status and sensitivities to EGFR‐TKIs were selected: H3255 (L858R), H1650 (del E746‐A750), and H1781 (wild‐type EGFR). Cells were treated with erlotinib, gefitinib, genistein, or the combination of each of the EGFR‐TKIs with genistein. Cell survival and apoptosis were assessed, and expression levels of EGFR, pAkt, cyclooxygenase‐2 (COX‐2), E‐cadherin, prostaglandin E₂ (PGE₂), and NF‐κB were measured.

RESULTS:

Both EGFR‐TKIs demonstrated growth inhibition and apoptosis in each of the cell lines, but H1650 and H1781 were much less sensitive. Genistein demonstrated some antitumor activity in all cell lines, but enhanced growth inhibition and apoptosis when combined with the EGFR‐TKIs in each of the cell lines. Both combinations down‐regulated NF‐κB significantly more than either agent alone in H3255. In addition, the combinations reduced the expression of EGFR, pAkt, COX‐2, and PGE_2, consistent with inactivation of NF‐κB.

CONCLUSIONS:

The authors concluded that genistein enhances the antitumor effects of EGFR‐TKIs in 3 separate NSCLC cell lines. This enhanced activity is in part because of greater reduction in the DNA‐binding activity of NF‐κB when EGFR‐TKIs were combined with genistein. Cancer 2009. © 2009 American Cancer Society.     

Enhancement of tumor radioresponse by combined treatment with gefitinib (Iressa, ZD1839), an epidermal growth factor receptor tyrosine kinase inhibitor, is accompanied by inhibition of DNA damage repair and cell growth in oral cancer

Molecular blockade of EGFR with either an EGFR MAb or an EGFR TKI enhances the radiosensitivity of human SCCs. In the present study, we investigated whether treatment with the EGFR TKI gefitinib (Iressa, ZD1839) improves the response to radiotherapy in the OSCC cell lines HSC2 and HSC3. We examined potential mechanisms that may contribute to the enhanced radiation response induced by gefitinib. Growth inhibition was observed in vitro with radiation or gefitinib. A cooperative antiproliferative effect was obtained when cancer cells were treated with radiation followed by gefitinib. Cells treated with a combination of radiation and gefitinib arrested in G(1) and G(2)-M phases, with a decrease in the S-phase population. While radiation alone did not significantly affect MEK1/2 and p38 MAPK autophosphorylation, the combination of gefitinib and radiation completely inhibited the downstream signaling of EGFR. Results from DNA damage repair analysis in cultured OSCC cells demonstrated that gefitinib had a strong inhibitory effect on DNA-PKc pathways after radiation. Tumor xenograft studies demonstrated that the combination of gefitinib and radiation caused growth inhibition and tumor regression of well-established OSCC tumors in athymic mice; tumor volume was reduced from 1,008.2 to 231.4 mm(3) in HSC2 cells (p < 0.01) and from 284.2 to 12.4 mm(3) in HSC3 cells (p < 0.01). Immunohistochemical analysis of OSCC xenografts revealed that gefitinib caused a striking decrease in tumor cell proliferation when combined with radiotherapy. Overall, we conclude that gefitinib enhances tumor radioresponse by multiple mechanisms that may involve antiproliferative growth inhibition and effects on DNA repair after exposure to radiation.     

Additive interaction of gefitinib ('Iressa', ZD1839) and ionising radiation in human tumour cells in vitro

Cultures of human carcinoma A-431, A-549 and HeLa cells were challenged with gamma-rays without or with concomitant exposure to gefitinib, a potent inhibitor of the tyrosine kinase activity of epidermal growth factor receptor (EGFR). The outcome of treatment was determined from cell and colony count, cell cycle progression and DNA double-strand break formation and rejoining. Apoptosis was measured in parallel from hypodiploid DNA and using an annexin V assay. Gefitinib developed a cytostatic effect in all cell lines, with drug sensitivity correlating the level of EGFR expression. A weak cytotoxicity of gefitinib was observed in HeLa cells only, although the drug was unable to induce significant cell cycle redistribution in this cell line. In contrast, substantial G1 block and S-phase depletion was observed in A-431 and A-549 cells exposed to gefitinib. The drug brought about additive to subadditive interaction with radiation with regard to growth inhibition, clonogenic death and induction of apoptosis. Consistently, gefitinib did not hinder the rejoining of radiation-induced DNA double-strand breaks in any cell line. The results demonstrate that gefitinib may elicit cytotoxicity at high concentration, but does not act as a radiosensitiser in vitro in concomitant association with radiation.     

Gefitinib ('Iressa', ZD1839), a selective epidermal growth factor receptor tyrosine kinase inhibitor, inhibits pancreatic cancer cell growth, invasion, and colony formation

Pancreatic cancer is a devastating malignancy, characterized by low responsiveness to conventional chemotherapies. Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) has shown clinical activity against EGFR-expressing tumors. Since pancreatic cancers frequently overexpress EGFR (ErbB-1) and its ligands, our aim was to investigate the potential role of gefitinib in this disease. The GI50 of gefitinib as well as the effects of gefitinib on growth factor actions in pancreatic cancer cell lines were analyzed using MTT assays. FACS analysis using Annexin and propidium iodide (PI) staining were performed to study cell cycle, apoptosis and cell death. Western blot analysis was carried out to investigate expression levels of the 4 members of the ErbB family of receptors in pancreatic cancer cell lines, as well as MAP kinase and EGFR phosphorylation. Soft agar assays were used to measure colony formations. Invasiveness of cancer cells was analyzed using Matrigel-coated filters. gefitinib inhibited cell proliferation of pancreatic cancer cell lines with GI50 concentrations ranging from 2.5 to over 10 micro M. Gefitinib completely inhibited EGF-induced cell proliferation, but did not significantly influence insulin-like growth factor (IGF)-induced mitogenesis. Gefitinib also completely abolished EGF-induced phosphorylation of EGFR and MAP kinase. Furthermore, gefitinib inhibited basal and EGF-induced anchorage-independent cell growth and invasion. Our data demonstrate that gefitinib inhibits pancreatic cancer cell growth through EGFR-dependent pathways. Gefitinib also inhibits anchorage-independent growth and invasiveness, suggesting that gefitinib may offer a new approach for the treatment of pancreatic cancer.     

Response to dual blockade of epidermal growth factor receptor (EGFR) and cycloxygenase-2 in nonsmall cell lung cancer may be dependent on the EGFR mutational status of the tumor

BACKGROUND: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated clinical benefit in patients with nonsmall cell lung cancer (NSCLC), particularly those with tumors that have EGFR-TK domain mutations. Moreover, the EGFR and cyclooxygenase (COX)-2 pathways are known to enhance the procarcinogenic effects of each other in different tumor types. Therefore, it was hypothesized that tumor EGFR mutation status may influence the effectiveness of simultaneous EGFR and COX-2 inhibition in patients with NSCLC. METHODS: Three NSCLC cell lines with varying EGFR mutation status and sensitivities to EGFR-TKIs were selected: H3255 (L858R), H1650 (del E746-A750), and H1781 (wild-type EGFR). Cells were treated with erlotinib, gefitinib, or celecoxib alone, and the combination of both EGFR-TKI inhibitors with celecoxib. Cell survival and apoptosis was assessed and correlated with the expression of COX-2, EGFR, pEGFR, Akt, pAkt, expression, and derived prostaglandin E2 (PGE(2)). RESULTS: Celecoxib by itself was found to have no effects on cell growth or apoptosis in any of the cell lines. Erlotinib and gefitinib inhibited cell growth and induced apoptosis in both mutant cell lines and did so in H1781 cells at 10-fold higher concentrations. Celecoxib when added to erlotinib or gefitinib significantly enhanced the antiproliferative and proapoptotic effects in both mutant cell lines but had no additional effects in H1781 cells. Greater down-regulation of COX-2, EGFR, pEGFR, Akt, pAkt, and PGE(2) was found when H3255 cells were treated with the combination compared with any of the single agents alone. CONCLUSIONS: The results of the current study demonstrate that the effectiveness of the addition of celecoxib to an EGFR-TKI is significantly greater in NSCLC cells with EGFR mutations, which is likely due to more complete inhibition of both pathways.     

Gefitinib ('Iressa', ZD1839), an epidermal growth factor receptor tyrosine kinase inhibitor, up-regulates p27KIP1 and induces G1 arrest in oral squamous cell carcinoma cell lines

High expression of epidermal growth factor receptor (EGFR) is frequently observed in many solid tumor types including oral squamous cell carcinomas (OSCC). Recently, the results of preclinical studies and early clinical trials targeting the EGFR have shown evidence of the activity. In this study, gefitinib ('Iressa', ZD1839), an EGFR-tyrosine kinase inhibitor, inhibited cell proliferation and upregulated p27KIP1 in OSCC cells. Growth inhibition was observed in OSCC xenografts when mice were treated with gefitinib in vivo. A flow cytometric analysis demonstrated that treatment with gefitinib induced accumulation in G1 phase, accompanied by a decrease in the percentage of cells in S phase. Apoptosis was not seen in this study. Cell growth was inhibited by an increase of the cell cycle inhibitor p27KIP1 and a decrease of its ubiquitin ligase subunit Skp2.     

Heparin-binding epidermal growth factor-like growth factor isoforms and epidermal growth factor receptor/ErbB1 expression in bladder cancer and their relation to clinical outcome

BACKGROUND: Cleavage of membrane-anchored heparin-binding epidermal growth factor-like growth factor (proHB-EGF) yields a soluble HB-EGF isoform (sHB-EGF), which is an activating epidermal growth factor receptor (EGFR) ligand and a C-terminal fragment HB-EGF-C acting directly in the nucleus. In bladder cancer, overexpression of both HB-EGF and EGFR have been observed, but to the authors' knowledge the prognostic significance of different modes of HB-EGF signaling have remained unclear. METHODS: Expression and intracellular localization of HB-EGF and EGFR were examined by immunohistochemistry in paraffin-embedded specimens from 121 patients who underwent cystectomy for bladder cancer. Tumor stage was pTis/pT1 in 7 patients, pT2 in 41 patients, pT3 in 55 patients, and pT4 in 18 patients. Lymph node metastases were present in 32 patients. RESULTS: Using an antibody directed against the C-terminal domain, HB-EGF expression was detected in the cytoplasm or in the nucleus of tumor cells. EGFR staining was uniform at the plasma membrane. The actuarial 5-year cancer-specific survival of patients with tumors with predominant nuclear HB-EGF staining was 28% compared with 57% if HB-EGF staining was predominantly cytoplasmic (P = .027). Disease outcome of patients with a 'mixed' HB-EGF staining pattern was found to be between that of the 2 former groups. In agreement with previous studies, strong EGFR expression was associated with poor prognosis. Despite strong EGFR expression, predominant cytoplasmic HB-EGF staining was associated with a more favorable outcome, whereas a predominant nuclear pattern defined a subgroup with extremely poor prognosis (5-year tumor-specific survival of 55% vs 13%, respectively; P = .026). CONCLUSIONS: The current study results confirm that EGFR expression is significantly correlated with disease-specific mortality but that the outcome is also influenced by the mode of HB-EGF signaling. Additional nuclear HB-EGF signaling, indicative of increased cleavage of proHB-EGF, appears to enhance the adverse activities. Cytoplasmic HB-EGF staining likely reflects proHB-EGF, which may also exert antiproliferative effects.     

吉非替尼治疗晚期复治性非小细胞肺癌41例

Objective  We observe the curative effect, median survival time, time to progression, quality of life and adverse effect of patients with advanced refractory non-small cell lung cancer (NSCLC) after gefitinib (Iressa) treatment. Methods  Forty-one patients with grade IIIb to IV NSCLC previously treated with two chemotherapy including 85.4% of patients after second line therapy were chosen. The regimen was oral intake of gefitinib 250 mg once daily until the disease progression or toxic reaction has become intolerable. The patients were required to receive tumor evaluation before the treatment, one month, two month and every three months after Iressa administration. Results  All of 41 patients were evaluable for therapeutic effect. Without complete regression being observed, partial response rate (PR), stable disease (SD) and progression of disease (PD) were 43.9% (18/41), 34.1% (14/41) and 22.1% (9/41), respectively. The overall response rate was 43.9% (18/41) and disease control rate (PR + SD) was 78% (32/41). The response rate in male was 42.1%, while it in female was 45.5% (P > 0.05). Twenty-two of them (53.7%, 22/41) were still alive with 10.1 months of MST when the follow-up ended in November 2006. TTP and MST of patients who died was 2.7 and 5.0 months, respectively. The rate of symptom improvement was 78% of all patients with 13 months of MST of PR patients. The Karnofsky enhanced 20 ± 5 after 28 days treatment without 3–4 degree of reactive toxicity. Conclusion  Iressa has significant antitumor activity in advanced NSCLC patients who have previously failed in second or third line chemotherapy. Iressa is effective and safe for patients with poor performance status.     

Targeting epidermal growth factor receptor in lung cancer: Perspective from the Asia–Pacific region

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase of the ErbB family that is frequently overexpressed in non‐small cell lung cancer (NSCLC), and has been identified as a novel therapeutic target for lung cancer. The development of small molecule EGFR‐tyrosine kinase inhibitors (TKI) such as gefitinib and erlotinib has resulted in paradigm shift in the treatment of advanced NSCLC. The impact of EGFR‐TKI in the treatment of NSCLC is even greater in Asia–Pacific region because one of the greatest clinical benefits of EGFR‐TKI has been seen in patients of East Asian ethnicity. The discovery of somatic mutations in EGFR‐tyrosine kinase domain has so far answered some, but not all, of the questions regarding the clinical response to EGFR‐TKI in NSCLC. In addition, other molecular profiles such as KRAS mutations have also been found to play an important role in EGFR targeted therapy. In this article, we review EGFR targeted therapy in NSCLC with the focus on perspective from the Asia–Pacific region.     

Differential radiosensitisation by ZD1839 (Iressa), a highly selective epidermal growth factor receptor tyrosine kinase inhibitor in two related bladder cancer cell lines

The epidermal growth factor receptor (EGFR) is expressed in a wide variety of epithelial tumours including carcinoma of the bladder. Stimulation of the EGFR pathway is blocked by ZD1839 (Iressa), a highly selective EGFR tyrosine kinase inhibitor. Radical radiotherapy is an established organ sparing treatment option for muscle invasive bladder cancer and this study has explored the possibility for the use of ZD1839 as a radiosensitiser in this scenario. The effect of combination treatment with ZD1839 (0.01 microM) and ionising radiation in the established bladder cancer cell lines MGH-U1 and its radiosensitive mutant clone S40b was measured by clonogenic assays. A highly significant radiosensitising effect was seen in both cell lines (P < 0.001 for MGH-U1 and S40b cell lines). This effect was independent of the concentration of the drug and the duration of exposure prior to treatment with ionising radiation. Cell cycle kinetics of both cell lines was not significantly altered with ZD1839 (0.01 microM) as a single agent. A modest induction of apoptosis was observed with ZD1839 (0.01 microM) as a single agent, but a marked induction was observed with the combination treatment of ZD1839 and ionising radiation. These results suggest a potentially important role for ZD1839 in combination with radiotherapy in the treatment of muscle invasive bladder cancer.     

表皮生长因子、雄激素受体和表皮生长因子受体在肝癌组织中的表达及影响因素分析

目的探讨肝癌患者肝癌组织中的表皮生长因子(EGF)、雄激素受体(AR)、表皮生长因子受体(EGFR)的表达情况及临床意义。方法采用免疫组织化学染色法检测EGF、AR、EGFR在90例肝癌患者的肝癌组织和90例非肝癌患者的非肝癌组织中的表达情况,比较不同临床特征肝癌患者肝癌组织中EGF、AR、EGFR的表达情况,分析肝癌患者肝癌组织中EGF、AR、EGFR表达的影响因素。结果肝癌组织中的EGF、AR、EGFR的阳性表达率均明显高于非肝癌组织,差异均有统计学意义(P﹤0.01)。有肝炎史、Ⅲ+Ⅳ期、中低分化、有淋巴结转移的肝癌患者肝癌组织中EGF、AR、EGFR的阳性表达率均高于无肝炎史、Ⅰ+Ⅱ期、高分化、无淋巴结转移的肝癌患者,差异均有统计学意义(P﹤0.05);不同年龄、性别、肿瘤直径的肝癌患者肝癌组织中EGF、AR、EGFR的阳性表达率比较,差异均无统计学意义(P﹥0.05)。Logistic回归分析结果显示,有淋巴结转移、TNM分期为Ⅲ+Ⅳ期是肝癌患者肝癌组织中EGF、AR、EGFR表达的独立危险因素。结论EGF、AR、EGFR在肝癌患者的肝癌组织中呈高表达,且其表达与肝癌患者的淋巴结转移情况和TNM分期密切相关。     

Clinical signs, pathophysiology and management of skin toxicity during therapy with epidermal growth factor receptor inhibitors.

The last few years, new therapies targeting the epidermal growth factor receptor (EGFR) have shown their efficacy in the treatment of several types of cancer. Monoclonal antibodies against the EGFR (e.g. cetuximab, panitumumab) or EGFR tyrosine kinase inhibitors (e.g. gefitinib, erlotinib) are generally well tolerated and do not have the severe systemic side-effects usually seen with cytotoxic drugs. A considerable number of patients treated with these EGFR inhibitors, however, develop dermatological side-effects, most frequently an acneiform eruption but also xerosis, eczema, fissures, telangiectasia, hyperpigmentation, hair changes and paronychia with pyogenic granuloma. These skin effects appear to be mechanism-based linked to the inhibition of EGFR action but the exact pathophysiology remains elusive. Left untreated these dermatological side-effects could represent a threat to patient compliance. Therefore effective management is mandatory. Mild cases of acneiform eruption respond well to topical anti-inflammatory acne therapy, whereas tetracyclines are needed to treat moderate to severe cases. This review outlines the broad spectrum of cutaneous side-effects of EGFR inhibitors, discusses possible underlying mechanisms and provides practical guidelines for the management based on literature data and on personal experience.     

Multidrug transporter ABCG2 prevents tumor cell death induced by the epidermal growth factor receptor inhibitor Iressa (ZD1839, Gefitinib)

Iressa (ZD1839, Gefitinib), used in clinics to treat non-small cell lung cancer patients, is a tyrosine kinase receptor inhibitor that leads to specific decoupling of epidermal growth factor receptor (EGFR) signaling. Recent data indicate that Iressa is especially effective in tumors with certain EGFR mutations; however, a subset of these tumors does not respond to Iressa. In addition, certain populations have an elevated risk of side effects during Iressa treatment. The human ABCG2 (BCRP/MXR/ABCP) transporter causes cancer drug resistance by actively extruding a variety of cytotoxic drugs, and it functions physiologically to protect our tissues from xenobiotics. Importantly, ABCG2 modifies absorption, distribution, and toxicity of several pharmacologic agents. Previously, we showed that ABCG2 displays a high-affinity interaction with several tyrosine kinase receptor inhibitors, including Iressa. Here, we show that the expression of ABCG2, but not its nonfunctional mutant, protects the EGFR signaling-dependent A431 tumor cells from death on exposure to Iressa. This protection is reversed by the ABCG2-specific inhibitor, Ko143. These data, reinforced with cell biology and biochemical experiments, strongly suggest that ABCG2 can actively pump Iressa. Therefore, variable expression and polymorphisms of ABCG2 may significantly modify the antitumor effect as well as the absorption and tissue distribution of Iressa.     

Changes in angiogenic growth factor levels after gefitinib treatment in non-small cell lung cancer

BACKGROUND: To investigate the changes in angiogenic growth factor expression before and after gefitinib treatment, and the association between this expression and response to gefitinib treatment, we measured circulating levels of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), matrix metalloproteinase (MMP) -2 and -9, and tissue inhibitors of metalloproteinase (TIMP) -1 and -2 in patients with non-small cell lung cancer (NSCLC). METHODS: Serum and plasma samples were collected from 52 patients before and after gefitinib treatment. The levels of VEGF, bFGF, MMP-2, MMP-9, TIMP-1 and TIMP-2 were measured using a sandwich enzyme immunoassay kit. RESULTS: Of the 52 patients, 17 (32.7%) achieved a partial response, 19 (36.5%) had stable disease and 16 (30.8%) had progressive disease. The levels of VEGF, bFGF, MMP-2, MMP-9, TIMP-1 and TIMP-2 did not change significantly after gefitinib treatment, even in responders. The levels of VEGF in volunteers, responders and non-responders were 384 +/- 86.4, 404 +/- 94.3 and 719 +/- 99.8 pg/ml, respectively. The difference between volunteers and responders was not significant (P = 0.540), while the differences between volunteers and non-responders (P = 0.031), and responders and non-responders (P = 0.028) were significant. CONCLUSIONS: Although our results indicate that gefitinib treatment does not affect circulating levels of angiogenic growth factors even in patients who showed a response to gefitinib treatment, low levels of VEGF may predict response to gefitinib treatment in patients with NSCLC.     

Predicting response to epidermal growth factor receptor-targeted therapy in colorectal cancer

The discovery over 20 years ago by the Nobel Laureate Stanley Cohen of epidermal growth factor and its receptor, followed by the recognition that this receptor is overexpressed in multiple cancer types, has been of phenomenal significance. From these events the ‘Holy Grail’ of targeted therapy has looked increasingly realistic. Over the last 5 years this work has come of age with the licensing of multiple agents targeting this important mitogenic pathway in multiple tumor types. However, these agents and the technology behind them, while impressive, have resulted in lower clinical response rates than anticipated. In this review we will focus on the epidermal growth factor receptor-targeted therapies in colorectal cancer, why our expectations from these therapies have not yet been fulfilled and how we may predict those cancers that are likely to respond or be resistant to these therapies through a greater appreciation of the intricacy, diversity and dynamism of cellular signaling mechanisms.