Epidermal growth factor receptor and K-Ras mutations and resistance of lung cancer to insulin-like growth factor 1 receptor tyrosine kinase inhibitors

BACKGROUND:

Most patients with nonsmall cell lung cancer (NSCLC) have responded poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). The authors investigated the involvement of insulinlike growth factor 1 receptor (IGF‐1R) signaling in primary resistance to EGFR TKIs and the molecular determinants of resistance to IGF‐1R TKIs.

METHODS:

Phosphorylated IGF‐1R/insulin receptor (pIGF‐1R/IR) was immunohistochemically evaluated in an NSCLC tissue microarray. The authors analyzed the antitumor effects of an IGF‐1R TKI (PQIP or OSI‐906), either alone or in combination with a small‐molecular inhibitor (PD98059 or U0126) or with siRNA targeting K‐Ras or mitogen‐activated protein kinase/extracellular signal‐regulated kinase kinase (MEK), in vitro and in vivo in NSCLC cells with variable histologic features and EGFR or K‐Ras mutations.

RESULTS:

pIGF‐1R/IR expression in NSCLC specimens was associated with a history of tobacco smoking, squamous cell carcinoma histology, mutant K‐Ras, and wild‐type (WT) EGFR, all of which have been strongly associated with poor response to EGFR TKIs. IGF‐1R TKIs exhibited significant antitumor activity in NSCLC cells with WT EGFR and WT K‐Ras but not in those with mutations in these genes. Introduction of mutant K‐Ras attenuated the effects of IGF‐1R TKIs on NSCLC cells expressing WT K‐Ras. Conversely, inactivation of MEK restored sensitivity to IGF‐TKIs in cells carrying mutant K‐Ras.

CONCLUSIONS:

The mutation status of both EGFR and K‐Ras could be a predictive marker of response to IGF‐1R TKIs. Also, MEK antagonism can abrogate primary resistance of NSCLC cells to IGF‐1R TKIs. Cancer 2012. © 2012 American Cancer Society.     

Epidermal growth factor receptor protein expression and genomic alterations in renal cell carcinoma

BACKGROUND:

Epidermal growth factor receptor (EGFR) is involved in the progression of many cancer types and represents an important therapeutic target.

METHODS:

To determine the role of EGFR in renal cell carcinoma (RCC), the authors analyzed 1088 tumors in a tissue microarray format by using immunohistochemistry and fluorescence in situ hybridization (FISH). A subset of 63 cancers was sequenced for EGFR exon 18 through 21 mutations.

RESULTS:

EGFR expression was observed in 83.8% of clear cell carcinomas, in 68.2% of papillary carcinomas, in 75% of chromophobe carcinomas, and in 50% of oncocytomas. Within clear cell carcinomas, the expression level of EGFR was associated with high tumor grade (P < .0001), advanced pathologic tumor classification (P < .0001), and, to a lesser extent, lymph node status (P = .0326). FISH analysis revealed increased EGFR copy numbers (high polysomy) in 5.5% of tumors and amplification in 0.1% of tumors. EGFR copy number increases were associated with EGFR protein expression (P = .0015). Within clear cell carcinomas, EGFR copy number increases were associated with high tumor grade (P < .0001), advanced pathologic tumor classification (P = .0472), and lymph node status (P = .0065). No exon 18 through 21 mutations were identified in 63 sequenced tumors.

CONCLUSIONS:

The authors concluded that increased EGFR expression occurs in a fraction of patients who have RCC with an unfavorable histologic phenotype. EGFR copy number gain represents 1 possible cause for EGFR overexpression; however, many over expressing tumors have a normal genotype. High polysomy (which is suggested to be predictive of a response to tyrosine kinase inhibitors) occurs in 5.6% of RCCs. Thus, the potential utility of anti‐EGFR medications may be worth further investigation in a small but significant subset of patients with RCC. Cancer 2012;. © 2011 American Cancer Society.     

Epidermal growth factor receptor expression in breast cancer association with biologic phenotype and clinical outcomes

BACKGROUND:

Epidermal growth factor receptor (EGFR) expression is associated with aggressive phenotypes in preclinical breast cancer models, but in clinical studies, EGFR has been inconsistently linked to poor outcome. We hypothesized that EGFR expression in human breast tumors, when centrally and uniformly assessed, is associated with an aggressive phenotype and resistance to systemic therapy.

METHODS:

In a database of 47,286 patients with breast cancer, EGFR status was known on 2567 tumors. EGFR levels were measured centrally by ligand binding assay, and tumors with ≥10 fmol/mg were prospectively deemed positive. Clinical and biological features of EGFR‐positive and EGFR‐negative tumors were compared. Clinical outcomes were assessed by systemic therapy status.

RESULTS:

Of 2567 tumors, 475 (18%) were EGFR positive. EGFR‐positive tumors were more common in younger and in black women, were larger, had a higher S‐phase fraction, and were more likely to be aneuploid. EGFR‐positive tumors were more likely to be HER2‐positive (26% vs 16%, P < .0001), but less likely to be estrogen receptor‐positive (60% vs 88%, P < .0001) or progesterone receptor‐positive (26% vs 65%, P < .0001). In multivariate analyses, EGFR expression independently correlated with worse disease‐free survival (hazard ratio [HR] = 1.66; 95% confidence interval [CI], 1.4‐2.41, P = .007) and overall survival (HR = 1.98, 95% CI, 1.36‐2.88, P = .0004) in treated patients, but not in untreated patients.

CONCLUSIONS:

EGFR expression is more common in breast tumors in younger and black women. It is associated with lower hormone receptor levels, higher proliferation, genomic instability, and HER2 overexpression. It is correlated with higher risk of relapse in patients receiving adjuvant treatment. Blocking EGFR may improve outcome in selected patients. Cancer 2010. © 2010 American Cancer Society.     

Bevacizumab reduces tumor targeting of antiepidermal growth factor and anti‐insulin‐like growth factor 1 receptor antibodies

Bevacizumab (antivascular endothelial growth factor [anti‐VEGF]) and cetuximab (antiepidermal growth factor receptor [anti‐EGFR]) are approved antibodies for treatment of cancer. However, in advanced colorectal cancer, the combination fails to improve survival. As the reason for the lack of activity is unknown, our study aims to determine the effect of bevacizumab on targeting of anti‐EGFR and insulin‐like growth factor 1 receptor (IGF‐1R) antibodies in tumors with single‐photon emission computed tomography (SPECT)/CT imaging. Mice with subcutaneous EGFR and IGF‐1R‐expressing SUM149 xenografts received a single dose of bevacizumab (10 mg/kg) or saline. After 4 days, mice were injected with radiolabeled cetuximab or R1507, an anti‐IGF‐1R antibody. A control group received a radiolabeled irrelevant IgG (hLL2). Three days later, SPECT/CT images were acquired and mice were dissected to determine the concentration of antibodies in the tissues. Tumors were analyzed immunohistochemically to determine vascular density (CD34), VEGF, EGFR and IGF‐1R expression. SPECT/CT imaging revealed that bevacizumab treatment significantly reduced tumor targeting of radiolabeled cetuximab by 40% from 33.1 ± 1.1 %ID/g to 19.8 ± 5.7 %ID/g (p = 0.009) for untreated and bevacizumab‐treated tumors, respectively. A similar effect was found for ¹¹¹In‐R1507: tumor targeting of R1507 decreased by 35%. No significant differences in tumor uptake were observed in mice that received an irrelevant IgG. Uptake in normal organs was not altered by bevacizumab. Immunohistochemical analysis showed that vascular density decreased with 43%, whereas EGFR and IGF‐1R expression was unaltered. In conclusion, bevacizumab treatment significantly reduces tumor targeting of anti‐EGFR and anti‐IGF‐1R antibodies. This emphasizes the importance of timing and sequencing of bevacizumab in combination with other antibodies.     

Insulin‐like growth factor‐1 receptor and phosphorylated AKT‐serine 473 expression in 132 resected thymomas and thymic carcinomas

BACKGROUND:

Thymic malignancies are rare tumors. The insulin‐like growth factor‐1 (IGF‐1)/IGF‐1 receptor (IGF‐1R) system is involved in the development of the thymus. IGF‐1R expression in thymic epithelial malignancies is unknown.

METHODS:

The authors investigated the expression of IGF‐1R and phosphorylated AKT serine 473 (p‐AKT) by using immunohistochemistry and examined the clinicopathologic correlations in a retrospective, single‐institution surgical series of 132 patients with thymic epithelial malignancies.

RESULTS:

Earlier disease stage, less aggressive histologic types, and complete resection were significant positive prognostic factors for disease‐related survival and progression‐free survival, and being a woman was a better prognostic factor for disease‐related survival. IGF‐1R and p‐AKT protein levels were expressed in 20% and 36% of thymic tumors, respectively. Both markers were expressed more commonly in recurrent disease than in primary tumors, in more aggressive subtypes, and in more advanced disease stages. There was a trend toward better survival and progression‐free survival in patients who were negative for IGF‐1R or p‐AKT expression in the whole series. When only the 91 primary tumors, IGF1R expression was associated with worse progression‐free survival (P < .001).

CONCLUSIONS:

The current retrospective analysis demonstrated that disease stage, tumor histology, sex, and resection type were major prognostic factors in the survival of patients with thymic malignancies. The expression levels of IGF‐1R and p‐AKT in thymic tumors suggested that IGF‐1R is a potential target for treatment. Cancer 2010. Published 2010 by the American Cancer Society.     

Quantitative determination of insulin-like growth factor 1 receptor mRNA in formalin-fixed paraffin-embedded tissues of invasive breast cancer

Background

Insulin-like growth factor 1 receptor (IGF1R) has recently received much attention due to its role in initiation and progression of breast cancer. Previously analysis of its gene expression has been restricted to fresh-frozen (FF) samples, but application of this technique to routinely processed formalin-fixed paraffin-embedded (FFPE) samples could facilitate larger retrospective studies correlating IGF1R expression with prognosis and therapeutic response.

Methods

A series of 77 paired FFPE and FF specimens of breast tumors was used to evaluate the possibility of quantifying IGF1R gene expression with FFPE samples and to compare the results obtained from FFPE and FF samples. The feasibility and prognostic value of analyzing IGF1R gene expression using FFPE samples was evaluated in a cohort of 260 primary breast tumors.

Results

Total RNA was extracted from 95.4% of the FFPE samples with concentration at least 30?ng/??L. Real-time PCR based on Taqman methodology was successful in 90% of the FFPE samples. IGF1R gene expression showed strong correlation not only between FFPE and FF (Spearman ???=?0.74), but also with IGF1R protein expression in both types of specimen. Kaplan?CMeier analysis showed that higher IGF1R mRNA expression was associated with longer recurrence-free survival (P?=?0.009) and breast cancer-specific survival (P?=?0.0002).

Conclusions

Quantitative analysis of IGF1R gene expression in FFPE tissues can be feasibly and reliably conducted, and provides information relevant to the characteristics and outcome of invasive breast cancer.     

Clinical impact of amphiregulin expression in patients with epidermal growth factor receptor (EGFR) wild‐type nonsmall cell lung cancer treated with EGFR‐tyrosine kinase inhibitors

BACKGROUND:

In patients with nonsmall cell lung cancer (NSCLC), several studies have demonstrated a positive correlation between somatic mutation in the epidermal growth factor receptor (EGFR) tyrosine kinase domain and clinical outcomes with the use of EGFR tyrosine kinase inhibitors (TKIs). However, some patients with wild‐type (WT) EGFR also responded to EGFR TKIs and remained stable. Recently, amphiregulin (AR) has been suggested as a predictive marker for EGFR TKIs in patients with WT EGFR‐positive NSCLC. The objective of the current study was to evaluate the association between AR expression and the efficacy of using EGFR TKIs in the treatment of patients with WT EGFR‐positive NSCLC.

METHODS:

Seventy‐three patients with WT EGFR‐positive NSCLC received treatment with gefitinib or erlotinib between May 2005 and December 2008. AR expression was assessed by immunohistochemistry.

RESULTS:

The clinical response to EGFR TKIs was reassessed for all patients as follows: 16 of 73 patients had a partial response (21.9%), 12 patients had stable disease (16.5%), and 45 patients had progressive disease (61.6%). AR expression was positive in 24 of 40 patients (60%). The ability to achieve disease control did not differ significantly between AR‐positive patients and AR‐negative patients (P = .188). At a median follow‐up of 25.4 months (range, 10.5‐53.3 months), progression‐free survival was 8.1 weeks in AR‐positive patients and 4 weeks in AR‐negative patients (P = .025), and overall survival was significantly longer in AR‐positive patients than in AR‐negative patients (12.2 months vs 4.1 months; P = .001).

CONCLUSIONS:

The current results suggested that patients with WT EGFR‐positive NSCLC who have AR‐positive tumors may benefit clinically from treatment with EGFR TKIs, indicating that AR expression may be a potential marker for the selection of EGFR‐TKI treatment for patients with WT EGFR‐positive NSCLC. Cancer 2011. © 2010 American Cancer Society.     

Epidermal growth factor receptor and AKT1 gene copy numbers by multi‐gene fluorescence in situ hybridization impact on prognosis in breast cancer

The epidermal growth factor receptor (EGFR)/PI3K/AKT signaling pathway aberrations play significant roles in breast cancer occurrence and development. However, the status of EGFR and AKT1 gene copy numbers remains unclear. In this study, we showed that the rates of EGFR and AKT1 gene copy number alterations were associated with the prognosis of breast cancer. Among 205 patients, high EGFR and AKT1 gene copy numbers were observed in 34.6% and 27.8% of cases by multi‐gene fluorescence in situ hybridization, respectively. Co‐heightened EGFR/AKT1 gene copy numbers were identified in 11.7% cases. No changes were found in 49.3% of patients. Although changes in EGFR and AKT1 gene copy numbers had no correlation with patients' age, tumor stage, histological grade and the expression status of other molecular makers, high EGFR (P = 0.0002) but not AKT1 (P = 0.1177) gene copy numbers correlated with poor 5‐year overall survival. The patients with co‐heightened EGFR/AKT1 gene copy numbers displayed a poorer prognosis than those with tumors with only high EGFR gene copy numbers (P = 0.0383). Both Univariate (U) and COX multivariate (C) analyses revealed that high EGFR and AKT1 gene copy numbers (P = 0.000 [U], P = 0.0001 [C]), similar to histological grade (P = 0.001 [U], P = 0.012 [C]) and lymph node metastasis (P = 0.046 [U], P = 0.158 [C]), were independent prognostic indicators of 5‐year overall survival. These results indicate that high EGFR and AKT1 gene copy numbers were relatively frequent in breast cancer. Co‐heightened EGFR/AKT1 gene copy numbers had a worse outcome than those with only high EGFR gene copy numbers, suggesting that evaluation of these two genes together may be useful for selecting patients for anti‐EGFR‐targeted therapy or anti‐EGFR/AKT1‐targeted therapy and for predicting outcomes.     

The prognostic significance of epidermal growth factor receptor expression in clear-cell renal cell carcinoma: a call for standardized methods for immunohistochemical evaluation

Background

Epidermal growth factor receptor (EGFR) is overexpressed in the majority of clear-cell renal cell carcinomas (RCCs). The prognostic significance of EGFR overexpression after nephrectomy, however, is controversial because of different methods used in the immunohistochemical (IHC) evaluation of EGFR expression.

Patients and Methods

In this study, we evaluated EGFR expression and its prognostic significance using 3 IHC evaluation methods. A tissue microarray composed of 44 cases of clear-cell RCC was stained for the patterns of EGFR overexpression, including membranous, cytoplasmic (EGFR-c), and total (membranous and cytoplasmic), and the percentage of cells positive for EGFR overexpression were recorded. An EGFR composite score was calculated by multiplying the total EGFR overexpression score (0-3) and percentage of positive cells.

Results

Membranous EGFR overexpression was detected in 38 of 44 cases (93.2%), with moderate to strong staining (scores 2 and 3) in 35 cases (79.5%). EGFR-c was detected in 28 cases (63.6%), with moderate to strong staining (scores 2 and 3) in 16 cases (36.4%). EGFR-c was significantly associated with pathologic stage (P = 0.003) and Fuhrman nuclear grade (P = 0.042). Epidermal growth factor receptor composite score correlated with pathologic stage (P = 0.045) but not Fuhrman nuclear grade. However, EGFR expression did not correlate with overall survival or disease recurrence.

Conclusion

This study demonstrates that the prognostic value of EGFR overexpression differs significantly when different methods are used to evaluate EGFR expression by IHC. Future studies should use standardized methods to evaluate the EGFR staining pattern and intensity and the percentage of positive cells in order to clarify the prognostic significance of EGFR overexpression in clear-cell RCC.     

Epidermal growth factor receptor mutations detected by denaturing high‐performance liquid chromatography in nonsmall cell lung cancer

BACKGROUND:

Somatic mutations in the epidermal growth factor receptor (EGFR) kinase domain are associated with sensitivity to EGFR‐tyrosine kinase inhibitors (EGFR‐TKI) in patients with nonsmall cell lung cancer (NSCLC).

METHODS:

The authors tested the possibility that nucleotide sequencing may be poorly suited for detection of mutations in tumor samples and found that denaturing high‐performance liquid chromatography (dHPLC) was an efficient and more sensitive method for screening.

RESULTS:

These results suggested that some reports based on standard DNA sequencing techniques may have underestimated mutation rates. In the present report, the authors examined the relationship between the presence and type of EGFR mutations detected by dHPLC and various clinicopathologic features of NSCLC, including response to therapy with EGFR‐TKI. Among 251 patients with advanced disease, 100 individuals received EGFR‐TKI. Those whose tumors harbored a detectable EGFR kinase mutation were much more likely to have a partial response (PR) or stable disease (SD) with EGFR‐TKI therapy than patients whose tumor contained no mutation (80% vs 35%; P = .001). Among the individual genotype subgroups, the frequency of a PR or SD was significantly different between patients with an exon 19 deletion compared with those with no detectable mutation (86% vs 35%; P < .001). Furthermore, patients whose tumors expressed an exon 19 mutant EGFR isoform exhibited a trend toward better EGFR‐TKI response (86% vs 67%; P = .171) and improved survival compared with patients whose tumors expressed an exon 21 mutation.

CONCLUSIONS:

Our findings warrant confirmation in large prospective trials and exploration of the biological mechanisms of the differences between mutation types. Cancer 2010. © 2010 American Cancer Society.     

Dual inhibition of epidermal growth factor and insulin-like 1 growth factor receptors reduce intestinal adenoma burden in the Apc(min/+) mouse

Background:

Identification of early molecular pathway changes may be useful as biomarkers for tumour response/resistance prediction, and here we provide direct in vivo proof of this concept. The type 1 insulin-like growth factor receptor (IGF1R) has been implicated in various aspects of adenoma development and metastasis. We show here that, in murine intestinal adenomas acutely exposed to a small molecular inhibitor of EGFR (gefitinib), there is concurrent suppression of EGFR downstream signalling and induction of IGF signalling. We therefore tested the hypothesis that blockade of EGFR signalling was being tempered by compensatory activation of the IGF pathway by examining the effect of chronic suppression of IGF1R using AZ12253801, a small molecular tyrosine kinase inhibitor of IGF1R.

Methods:

Male Apc^min/+ mice with an intestinal tumour burden were exposed to a single dose of an inhibitor against EGFR (gefitinib), IGF1R (AZ12253801), 0.5% Tween 80 or combined EGFR/IGF1R inhibitor and culled 4 h post dosing. Tumour tissue was analysed to detect the early molecular pathways induced and anti-tumour phenotypic changes. Cohorts of male Apc^min/+ mice (n=15–17) were subsequently treated with gefitinib for a period of 8 weeks and subsequently exposed to single (either gefitinib or AZ12253801) or combined (gefitinib and AZ12253801) therapy. We also included a vehicle-treated cohort, which was never exposed to gefitinib and became symptomatic of the disease by day 150.

Results:

Both single treatments delayed the onset of disease symptoms. Combined dosing with gefitinib and AZ12253801 similarly delayed the onset of symptoms, and at 200 days suppressed small intestinal tumourigenesis more effectively than either treatment alone (median small intestinal adenoma volume (47 mm³ (comb) vs 248 mm³ (AZ12253801), P=0.0003 and 47 mm³ (comb) vs 123 mm³ (gefitinib), P=0.0042, Mann–Whitney (two-sided) test).

Conclusion:

Our data provide evidence in support of the use of combinatorial therapy, and establishes the need to further define the precise benefit in vivo.     

Insulin-like growth factor receptor 1 (IGF1R) expression and survival in surgically resected non-small-cell lung cancer (NSCLC) patients

BackgroundThe purpose of this study is to investigate the prognostic role of insulin-like growth factor receptor 1 (IGF1R) expression in surgically resected non-small-cell lung cancer (NSCLC).Patient characteristics and methodsThis retrospective study was conducted in 369 stage I–II–IIIA, surgically resected, NSCLC patients. Patients exposed to anti-epidermal growth factor receptor (EGFR) agents were excluded. IGF1R expression was evaluated by immunohistochemistry in tissue microarray sections.ResultsA positive IGF1R expression (score ≥ 100) was observed in 282 cases (76.4%) and was significantly associated with squamous cell histology (P = 0.04) and with grade III differentiation (P = 0.02). No difference in survival was observed between the positive and negative group when score 100 was used as cut-off for discriminating a positive versus a negative IGF1R result (52 versus 48 months, P = 0.99) or when median value of IGF1R expression was used (45 versus 55 months, P = 0.36). No difference in survival was observed between IGF1R-positive and -negative patients in a subgroup of stage I–II adenocarcinoma (n = 137) with known EGFR mutation and copy number status.ConclusionsIGF1R expression does not represent a prognostic factor in resected NSCLC patients. Patients with squamous cell carcinoma overexpress IGF1R more frequently than patients with nonsquamous histology, justifying the different sensitivity to anti-IGF1R agents observed in clinical trials.     

The insulin‐like growth factor 1 receptor causes acquired resistance to erlotinib in lung cancer cells with the wild‐type epidermal growth factor receptor

Epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitor (TKI) therapy often provides a dramatic response in lung cancer patients with EGFR mutations. In addition, moderate clinical efficacy of the EGFR‐TKI, erlotinib, has been shown in lung cancer patients with the wild‐type EGFR. Numerous molecular mechanisms that cause acquired resistance to EGFR‐TKIs have been identified in lung cancers with the EGFR mutations; however, few have been reported in lung cancers with the wild‐type EGFR. We used H358 lung adenocarcinoma cells lacking EGFR mutations that showed modest sensitivity to erlotinib. The H358 cells acquired resistance to erlotinib via chronic exposure to the drug. The H358 erlotinib‐resistant (ER) cells do not have a secondary EGFR mutation, neither MET gene amplification nor PTEN downregulation; these have been identified in lung cancers with the EGFR mutations. From comprehensive screening of receptor tyrosine kinase phosphorylation, we observed increased phosphorylation of insulin‐like growth factor 1 receptor (IGF1R) in H358ER cells compared with parental H358 cells. H358ER cells responded to combined therapy with erlotinib and NVP‐AEW541, an IGF1R‐TKI. Our results indicate that IGF1R activation is a molecular mechanism that confers acquired resistance to erlotinib in lung cancers with the wild‐type EGFR.     

Clinical impact of anti-epidermal growth factor receptor monoclonal antibodies in first-line treatment of metastatic colorectal cancer: meta-analytical estimation and implications for therapeutic strategies

BACKGROUND:

Antiepidermal growth factor receptor (anti‐EGFR) monoclonal antibodies (MoAbs) are indicated for the treatment of metastatic colorectal cancer patients, but some scientific issues concerning their efficacy are currently unsolved.

METHODS:

A literature‐based meta‐analysis was conducted. Hazard ratios (HRs) were extracted from randomized trials for progression‐free survival (PFS) and overall survival (OS); the event‐based risk ratio was derived for response. Sensitivity analyses to look for interactions according to KRAS status and chemotherapy association regimens were performed.

RESULTS:

Eight trials (6609 patients) were identified. A significant interaction according to KRAS status was found for PFS (wild type vs mutant, P = .001) and response rate (wild type vs mutant, P < .0001). The addition of an anti‐EGFR MoAb to first‐line chemotherapy increased PFS in the KRAS wild‐type population (HR, 0.91; 95% confidence interval [CI], 0.84‐0.99; P = .03), and had a detrimental effect in the KRAS mutant population (HR, 1.13; 95% CI, 1.03‐1.25; P = .013). A significant increase in the probability of achieving a response was evident in KRAS wild‐type patients (relative risk, 1.17; 95% CI, 1.04‐1.33; P = .011). In this population, the interaction in response rate according to adopted chemotherapy favored irinotecan‐containing regimens (P = .01), and at meta‐regression analysis the relative increase in response rate was significantly related to PFS (P = .00001) and OS (P = .00193) benefit.

CONCLUSIONS:

The addition of an anti‐EGFR MoAb to first‐line chemotherapy produces a clear benefit in response rate. This advantage is restricted to KRAS wild‐type patients and translates into a small benefit in PFS. At present, irinotecan‐based backbone chemotherapy could be a preferable option. The correlation between activity and survival parameters corroborates the hypothesis that anti‐EGFR MoAbs might be more suitable for patients needing tumoral shrinkage. Cancer 2011;. © 2011 American Cancer Society.     

A phase 2 study of the insulin-like growth factor-1 receptor inhibitor MK-0646 in patients with metastatic, well-differentiated neuroendocrine tumors

BACKGROUND:

Neuroendocrine tumor (NET) cell lines frequently express both insulin‐like growth factor (IGF) ligand and the cognate IGF‐1 receptor (IGF‐1R) and, as such, potentially depend on the activation of IGF‐1R and its downstream effectors for growth and survival. Preclinical studies suggest that somatostatin analogs and mammalian target of rapamycin (mTOR) inhibitors exhibit antitumor activity against NETs through inhibition of IGF‐1‐dependent signaling, suggesting that IGF‐1R inhibition may be a promising therapeutic approach to NETs. Therefore, the authors of this report evaluated the safety and efficacy of MK‐0646, a fully human monoclonal antibody (MoAb) that binds to the IGF‐1R, as monotherapy in patients with metastatic, well‐differentiated NETs.

METHODS:

A phase 2 study was performed in which patients received intravenous MK‐0646 10 mg/kg once weekly over 1 hour. Archived pretreatment tumor tissue was obtained and genotyped for v‐Ki‐ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), phosphatidylinositol‐3‐kinase, catalytic, alpha polypeptide (PIK3CA); and v‐raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations, and immunohistochemistry was performed to measure the expression IGF‐1R.

RESULTS:

Twenty‐five patients received treatment (40% women; median age, 61 years; age range, 37‐83 years), including 15 patients with carcinoid tumors and 10 patients with pancreatic NETs. No partial or complete responses were observed. The median progression‐free survival was 4.2 months in the pancreatic NET cohort (range, 0.7‐6.7 months) and 2.7 months in the carcinoid cohort (range, 2‐3 months). Serious adverse events that were potentially related to MK‐0646 included grade 3/4 hyperglycemia in 8 of 25 patients (32%), grade 2 hypersensitivity reaction in 1 of 24 patients (4%), and grade 3 lipase elevation in 1 of 25 patients (4%).

CONCLUSIONS:

Despite a compelling preclinical rationale, MK‐0646 was inactive as a single agent in well‐differentiated NETs. Further studies of MK‐0646 as a monotherapy in unselected NETs are unwarranted. Cancer 2012. © 2012 American Cancer Society.     

Insulin‐like growth factor 1 expression correlates with clinical outcome in K‐RAS wild type colorectal cancer patients treated with cetuximab and irinotecan

Seventy to 40% of K‐RAS wild type colorectal tumors does not seem to benefit from treatment with antiepidermal growth factor receptor (anti‐EGFR) monoclonal antibodies. Recent data suggested that in presence of IGF‐1 system, altered activation colorectal cancer cells may escape anti‐EGFR mediated cell death. The interaction between IGF‐1 expression and K‐RAS mutational analysis was tested to verify the ability of IGF‐1 to identify a subgroup of patients more likely to benefit from EGFR‐targeted antibodies treatment. IGF‐1 expression and K‐RAS mutational status was assessed in advanced colorectal cancer patients receiving irinotecan/cetuximab. One hundred twelve patients were analyzed. IGF‐1 was negative in 30 patients (27%) and overexpressed in the remaining 82 cases (73%). In IGF‐1 negative and IGF‐1 positive tumors, we observed progressive disease in 9 (30%) and 55 (67%) patients, respectively (p = 0.001). Median progression‐free survival was 7.5 mo in patients showing IGF‐1 negative tumors and 3 mo for IGF‐1 expressing tumors (p = 0.002). Among K‐RAS wild type patients, IGF‐1 negative and positive tumors showed a partial response to cetuximab‐irinotecan in 13 (65%) and 11 (22%) cases, respectively (p = 0.002). Median progression‐free survival in IGF‐1 negative tumors was 10 mo and 3.2 mo in IGF‐1 positive colorectal cancers (p = 0.02). IGF‐1 proved to be a possible predictive factor for resistance to anti‐EGFR monoclonal antibodies in K‐RAS wild type colorectal cancer. Combined IGF‐1 and K‐RAS analysis may represent an effective strategy for a better selection of responding colorectal cancer patients.     

Cell surface receptor expression patterns in osteosarcoma

BACKGROUND:

Although the presence of numerous cell signaling receptors in osteosarcoma is known, their simultaneous characterization has not been performed to date. The current study sought to characterize and quantify the expression of cell surface receptors across a variety of osteosarcoma cell lines.

METHODS:

Standard (n = 4) and patient‐derived (n = 10) osteosarcoma cell lines were cultured and labeled with antibodies to epidermal growth factor receptor, human epidermal growth factor receptor (HER)‐2, HER‐3, HER‐4, insulin‐like growth factor 1 receptor (IGF‐1R), IGF‐2R, insulin receptor (IR), vascular endothelial growth factor receptor (VEGFR)‐1, VEGFR‐2, VEGFR‐3, c‐Met, fibroblast growth factor receptor (FGFR)‐2, FGFR‐3, and platelet‐derived growth factor receptor (PDGFR)‐β. Cell surface examination was performed using flow cytometry, and the geometric fluorescent mean for each receptor was calculated and compared against a positive control.

RESULTS:

Significant overexpression of IGF‐2R was shown in all cell lines, with an average geometric mean above the upper expression quartile. A variable expression pattern was seen for c‐Met, PDGFR‐β, IR, IGFR‐1, HER‐2, and VEGFR‐3 with expression values for the remaining receptors mainly in the lower quartile. An apparent association between the expression of IGF‐1R and HER‐2 and between the expression of PDGFR‐β and IR was demonstrated.

CONCLUSION:

IGF‐2R was consistently overexpressed on the cell surface across all tested osteosarcoma cell lines. Substantial, although variable, expression of c‐Met, HER‐2, IGF‐1R, VEGFR‐3, IR, and PDGFR‐β was demonstrated as well, suggesting that these receptors may contribute to osteosarcoma aggressiveness and biological heterogeneity and may serve as potential targets within a subset of tumors. Associated receptor expression may provide new insight into common regulatory factors or pathways. Targeting either common factors or targeting multiple specific receptors may have therapeutic relevance. Cancer 2012;. © 2011 American Cancer Society.     

Phosphorylated insulin-like growth factor-1 receptor (pIGF1R) is a poor prognostic factor in brain metastases from lung adenocarcinomas

A greater understanding of brain metastases is imperative for developing novel therapeutic strategies. Our previous study showed that insulin-like growth factor (IGF) signaling pathway was activated in brain-tropic cancer cells. In this study, we investigated the clinical relevance of activated (phosphorylated) IGF-1 receptor (pIGF1R) expression in brain metastases originating from lung adenocarcinomas. All pathologically confirmed brain metastases from lung adenocarcinomas, with available archived specimens from January 1998 to December 2009 at National Taiwan University Hospital, were assessed immunohistochemically for pIGF1R expression using H-score criteria. A median H-score was used as a cutoff point to define high or low pIGF1R expression. The mutation status in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) was examined using direct sequencing. The prognostic significance of pIGF1R expression, its correlations with clinicopathological characteristics, and EGFR status were evaluated. In the 86 cases, high membranous/cytoplasmic pIGF1R expression in brain metastases correlated with a shorter median survival (10.8 vs 27.8 mo, P = 0.003). This correlation was more significant in patients with EGFR mutations [hazard ratio (HR) 2.38, 95 % confidence interval (CI) 1.19–4.77 for EGFR mutations; HR 1.99, 95 % CI 0.95–4.15 for EGFR wild type] and remained statistically significant in multivariate analysis after adjusting for the effects of other potential prognostic factors, including the graded prognostic assessment score, solitary brain metastasis, extracranial metastatic status, EGFR mutations, and treatment using EGFR tyrosine kinase inhibitors. Although we also identified nuclear pIGF1R expression, this result was prognostically non-significant. Our study results showed that high membranous/cytoplasmic pIGF1R expression in brain metastases was a poor prognostic factor, more significantly in patients with EGFR mutations than in those with wild-type EGFRs.