Angela Zupa

Mechanisms of resistance to EGFR tyrosine kinase inhibitors gefitinib/erlotinib and to ALK inhibitor crizotinib

The discovery of several molecular alterations that underlie non-small cell lung cancer (NSCLC) pathogenesis has led to the development of targeted therapies. In particular, gefitinib and erlotinib have become the standard of care in patients harboring epidermal growth factor receptor mutations, while crizotinib showed an impressive efficacy in patients with ALK-positive NSCLC. Nevertheless, the occurrence of clinical resistance limits the long term results of these novel agents. The identification of the molecular mechanisms responsible for acquired resistance to targeted therapy is crucial in order to pursue the creation of rational strategies to overcome resistance. In the current review, we will focus on the acquired resistance mechanisms to EGFR-TKIs and crizotinib and the therapeutic strategies currently under study to overcome resistance.

Protein pathway activation mapping of brain metastasis from lung and breast cancers reveals organ type specific drug target activation.

Brain metastases are the most common fatal complication of systemic cancer, especially of lung (40-50%) and breast (20-30%) cancers. In this era of personalized therapy, there is a critical need to uncover the signaling architecture of brain metastases; however, little is known about what signaling pathways are activated in the context of the brain microenvironment. Using a unique study set of 42 brain metastases from patients with breast or nonsmall cell lung cancer (NSCLC), the phosphorylation/activation states of 128 key signaling proteins involved in cancer signaling were measured in laser capture microdissected tumor epithelium using reverse phase protein microarray (RPMA) technology. Distinct pathway activation subgroups from both breast and lung metastases were underpinned by, among others, ERBB2, AKT, mTOR, EGFR, SMAD, and ERK-p38 signaling. Breast cancer metastases showed significantly (p < 0.05) higher activation of the c-ERBB2/IGFR-AKT pathway network compared to NSCLC metastases, whereas NSCLC metastases to the brain exhibited higher relative levels of many members of the EGFR-ERK signaling network. Protein pathway activation mapping using RPMA revealed both the heterogeneity of signaling networks in brain metastases that would require a prior stratification to targeted therapies as well as the requirement of direct analysis of the metastatic lesion.

A Pilot Characterization of Human Lung NSCLC by Protein Pathway Activation Mapping.

Background: An understanding of the activated protein signaling architecture in non–small-cell lung cancer (NSCLC) is of critical importance to the development of new therapeutic approaches and identification of predictive and prognostic biomarkers for patient stratification. Methods: We used reverse-phase protein microarrays to map the activated protein signaling networks of 47 NSCLC tumors, 28 of which were node negative, which were subjected to tumor cellular enrichment using laser capture microdissection. The phosphorylation/cleavage levels of 111 key signaling proteins and total levels of 17 proteins were measured for broadscale signaling analysis. Results: Pathway activation mapping of NSCLC revealed distinct subgroups composed of epidermal growth factor receptor (ERBB1), v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ERBB2), v-erb-b2 erythroblastic leukemia viral oncogene homolog 3 (ERBB3), v-erb-a erythroblastic leukemia viral oncogene homolog 4 (ERBB4), v-akt murine thymoma viral oncogene homolog 1- mammalian target of rapamycin (AKT-mTOR), protein kinase, AMP-activated, alpha 2 catalytic subunit (AMPK), and autophagy-related signaling, along with transforming growth factor-beta-signaling protein 1 (SMAD), insulin-line growth factor receptor (IGFR), rearranged during transfection proto-oncogene (RET), and activated CDC42-associated kinase (ACK) activation. Investigation of epidermal growth factor receptor (EGFR)-driven signaling identified a unique cohort of tumors with low EGFR protein expression yet high relative levels of phosphorylated EGFR and high EGFR total protein with low relative levels of phosphorylation. Last, mapping analysis of patients with NSCLC with N0 disease revealed a pilot pathway activation signature composed of linked epidermal growth factor receptor family (HER)-AMPK-AKT-mTOR signaling network along with focal adhesion kinase- LIM domain kinase-1 (FAK-LIMK) and janus kinase (JAK)-signal transducers and activators of transcription (STAT) pathways that correlated with short-term survival and aggressive disease. Conclusions: Functional protein pathway activation mapping of NSCLC reveals distinct activation subgroups that are underpinned by important therapeutic targets and that patients with early-stage node negative disease and poor prognosis may be identified by activation of defined, biochemically linked protein signaling events. Such findings, if confirmed in larger study sets, could help select and stratify patients for personalized targeted therapies.

Coexistence of two different mutations in codon 12 of the Kras gene in colorectal cancer: Report of a case supporting the concept of tumoral heterogeneity

Evaluation of the mutational status of KRAS is a crucial step for the correct therapeutic approach in treating advanced colorectal cancer as the identification of wild-type KRAS tumors leads to more specific and less toxic treatments for patients. Although several studies have highlighted the differences between primary and metastatic tumors, the possibility of two or more mutations in the same codon has seldom been reported. The present study reports an additional case of an advanced adenocarcinoma of the colon showing two somatic mutations (p.G12D and p.G12V) in the same codon (codon 12) of exon 2 of the KRAS gene, thus supporting the possibility of two differing clonal origins of the tumor. Although the clinical significance of multiple mutations remains unknown at present, based on the limited data available in the literature, this rare event appears to be associated with a more aggressive disease, as in the present case. This case report demonstrates the existence of intratumoral heterogeneity and the coexistence of distinct clones within a tumor that may have profound clinical implications for disease progression and therapeutic responses.

[F-18] FDG-PET/CT parameters as predictors of outcome in inoperable NSCLC patients.

Abstract Background. We evaluated the prognostic significance of standardized uptake value (SUVmax), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) in [F-18] FDG PET/CT findings in patients with inoperable non-small-cell lung cancer (NSCLC). Patients and methods. One hundred and three patients (mean age, 65.6 ± 16 years) underwent [F-18] FDG PET/CT before the chemotherapy. The SUVmax value, the MTV (cm3; 42% threshold) and the TLG (g) were registered. The patients were followed up to 18 months thereafter (range 12-55 months). Failure to respond without progression, progression and/or disease-related death constituted surrogate end-points. The optimal SUVmax, MTV and TLG cut-off to predict the patients’ outcome were estimated. PET/CT results were then related to disease outcome (progression free survival; PFS). Results. The Kaplan-Meier survival analysis for SUVmax showed a significant shorter PFS in patients presenting with lower values as compared to those with higher (p < 0.05, log-rank test). MTV and TLG were not suitable for predicting PFS apart from the subset of patients with mediastinal nodal involvement. Conclusions. Despite the availability of new tools for the quantitative assessment of disease activity on PET/CT, the SUVmax rather than MTV and TLG remains the only predictor for PFS in NSCLC patients. MTV holds a value only when concomitant nodal involvement occurs.

Pyrosequencing evaluation of low-frequency KRAS mutant alleles for EGF receptor therapy selection in metastatic colorectal carcinoma

AIM To evaluate whether pyrosequencing (PS) improves the KRAS mutational status predictive value. PATIENTS & METHODS A retrospective analysis of KRAS mutations by PS and direct sequencing (DS) in 192 metastatic colorectal carcinomas (mCRCs), subgrouped in 51 KRAS mutated at PS and 141 KRAS wild-type at DS. RESULTS DS failed to detect low-frequency KRAS mutations in four out of 51 mCRCs, whereas PS detected 12 additional low-frequency KRAS mutations in 141 mCRCs KRAS wild-type at DS. After reanalyzing by PS 97 KRAS wild-type tumors treated with anti-EGF receptor (EGFR) antibodies, nine additional mutations were revealed in nonresponders, whereas none of responders exhibited a KRAS-mutated genotype. Of note, KRAS-mutated tumors upon PS showed a worst progression-free survival after EGFR therapy. Finally, PS allowed the detection of additional NRAS, BRAF and exon 20 PIK3CA mutations mostly in KRAS wild-type mCRCs resistant to EGFR therapy. CONCLUSION PS detection of low-frequency mutations may improve the KRAS predictive value for EGFR therapy selection.

Role of preeclampsia-related angiogenic factors in sunitinib cardiotoxicity: two cases and review of the literature

Sunitinib is a multi-targeted tyrosine kinase inhibitor widely used in clear cell renal carcinoma and in imatinib-resistant gastrointestinal stromal tumors. Sunitinib-associated cardiotoxicity has been recognized and includes hypertension, left ventricular dysfunction and congestive heart failure; nevertheless, few data exist in the literature regarding the role of preeclampsia-related angiogenic factors in sunitinib cardiotoxicity. We report a case of sunitinib-induced severe left ventricular dysfunction that occurred in a hypertensive woman with metastatic renal carcinoma and a history of preeclampsia, and a case of sunitinib-induced preeclampsia-like syndrome in a normotensive patient with an imatinib-resistant gastrointestinal stromal tumor. Our experience confirms that inhibition of angiogenic factors to treat cancer is a novel challenge for the oncologist and requires the cardiologists support.