Caterina Fumagalli

Review Article: Pulmonary Sarcomatoid Carcinomas: A Practical Overview

Pulmonary sarcomatoid carcinomas (PSCs) are currently defined as poorly differentiated non-small-cell carcinomas containing a component with sarcoma or sarcoma-like (spindle and/or giant cell) features. They consist of 5 major histological variants, namely pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. The segregation of PSCs into a distinct clinicopathologic entity seems justified on the basis of morphologic, behavioral, and genotypic/phenotypic attributes. As a group, PSCs generally run an aggressive clinical course and may cause major difficulties in the differential diagnosis with other primary and secondary malignancies of the lung. At present, PSCs are believed to represent a family of carcinomas “in transition,” in which diverse pathways of clonal evolution account for histological differences of a common ancestor lesion. The sarcomatous or sarcomatoid component of these tumors is thought to derive from carcinoma cells during the progression of carcinogenesis through the activation of an epithelial—mesenchymal transition program leading to sarcomatous transformation or metaplasia (conversion paradigm). Conceivably, targeting the epithelial—mesenchymal transition program could become a valid therapeutic strategy for these life-threatening tumors, whose sensitivity to current medical manipulation is disappointing.

Activity of epidermal growth factor receptor-tyrosine kinase inhibitors in patients with non-small cell lung cancer harboring rare epidermal growth factor receptor mutations.

Introduction: Mutations of the epidermal growth factor receptor (EGFR) have been proven to predict activity of the EGFR-tyrosine kinase inhibitors (EGFR-TKI), gefitinib and erlotinib. Although the “common” EGFR mutations, such as the L858R point mutation in exon 21 and the in-frame deletional mutation in exon 19, have been definitively associated with response to EGFR-TKIs, the correlation with response to treatment for many other rarer mutations is still unclear. In this study, we report the results of treating patients with advanced non-small cell lung cancer harboring rare EGFR mutations treated with EGFR-TKIs. Methods: The frequency of rare mutations has been investigated in 681 cases of non-small cell lung cancer screened between 2006 and 2010. Mutations in exons 18 and 20, uncommon mutations in exons 19 and 21, and/or the presence of different mutations in a single tumor (complex mutations) were considered rare. Results: EGFR mutations were detected in 99 tumors (14.5%). Eighteen cases carried rare mutations, and 10 of these patients were treated with erlotinib or gefitinib. The clinical outcome was described case by case with references to the literature. Of note, we found two EGFR mutations never identified before and one of unknown response to EGFR-TKIs. Conclusions: Gefitinib and erlotinib have different antitumor activity according to the type of the EGFR mutation borne. Report of cases harboring rare mutations can support the decision-making process in this subset of patients.

Frequent mutations in the neurotrophic tyrosine receptor kinase gene family in large cell neuroendocrine carcinoma of the lung.

The neurotrophic tyrosine receptor kinase (NTRK) family is potentially implicated in tumorigenesis and progression of several neoplastic diseases, including lung cancer. We investigated a large number of pulmonary neuroendocrine tumors (PNETs) and non‐small cell lung carcinomas (NSCLCs) without morphological evidence of neuroendocrine differentiation for mutations in the NTRK gene family. A total of 538 primary lung carcinomas, including 17 typical carcinoids (TCs), 10 atypical carcinoids (ACs), 39 small cell lung carcinomas (SCLCs), 29 large cell neuroendocrine carcinomas (LCNECs), and 443 NSCLCs were evaluated by single‐strand conformation polymorphism (SSCP) and sequencing of the tyrosine kinase domain (TKD) of NTRK1, NTRK2, and NTRK3. The NTRK1 gene was never found to be mutated. A total of 10 somatic mutations were detected in NTRK2 and NTRK3, mostly located in the activating and catalytic loops. NTRK mutations were seen in 9 (10%) out of 95 PNETs but in 0 out of 443 NSCLCs investigated. No mutations were observed in TCs, ACs, and SCLCs. Interestingly, all the mutations were restricted to the LCNEC histotype, in which they accounted for 31% of cases. A mutational analysis, performed after microdissection of LCNECs combined with adenocarcinoma (ADC), showed that only neuroendocrine areas were positive, suggesting that NTRK mutations are involved in the genesis of the neuroendocrine component of combined LCNECs. Our data indicate that somatic mutations in the TKD of NTRK genes are frequent in LCNECs. Such mutational events could represent an important step in the cancerogenesis of these tumors and may have potential implications for the selection of patients for targeted therapy. Hum Mutat 29(5), 609–616, 2008.

Temozolomide in Advanced Neuroendocrine Neoplasms: Pharmacological and Clinical Aspects

Alkylating agents, such as streptozocin and dacarbazine, have been reported as active in neuroendocrine neoplasms (NENs). Temozolomide (TMZ) is an oral, potentially less toxic derivative of dacarbazine, which has shown activity both as a single agent and in combination with other drugs. Nevertheless, its role in NENs has not been well defined. Several retrospective and prospective phase I-II studies have been published describing its use in a variety of NENs. In a retrospective series, the combination of capecitabine and TMZ was reported to be associated with a particularly high tumour response in pancreatic NENs as a first-line treatment. Although in NENs, determination of the O6-methylguanine-DNA methyltransferase (MGMT) status has been suggested as a predictive biomarker of response, its role still remains investigational, awaiting validation along with the establishment of the optimal detection method. Metronomic schedules have been reported to potentially overcome MGMT-related drug resistance. Toxicity is manageable if well monitored. We reviewed the literature regarding pharmacological and clinical aspects of TMZ, focusing on specific settings of NENs, different schedules, toxicity and safety profiles, and potential predictive biomarkers of response.

Pathologic and molecular features of screening low-dose computed tomography (LDCT)-detected lung cancer : A baseline and 2-year repeat study

Detailed studies on the pathologic and molecular features of low-dose computed tomography (LDCT)-detected carcinomas and comparison with unscreened tumors are still lacking. We evaluated the histopathologic features of 89 LDCT-detected lung cancers resected between 2004 and 2006. These tumors occurred within a cohort of 5202 volunteers undergoing annual LDCT, aged > or =50 years, and with a minimum 20 pack-year index. In adenocarcinomas, central scar diameter, invasion foci size and K-ras mutations were also assessed. The results were compared with those of 89 consecutive lung carcinomas matched for confounding factors (sex, smoking habit), selected from group of 363 consecutive clinically worked-up lung cancer, surgically resected in the same period and at the same Institution. The tumors were diagnosed in 63 males and 26 females (range 50-79 years), 55 of which diagnosed at the baseline (1.05%) and 34 (including 10 repeat cancers) operated after work-up during the second year (0.72%). LDCT-detected tumors showed high resectability rate (89%), earlier stage (63%) and prevalence of adenocarcinoma nodules (72%), most often of the mixed subtype, in comparison with unscreened tumors. A similar prevalence of K-ras mutations was found in both screened and unscreened adenocarcinomas. Repeat cancers were found in 10 screened patients, and were predominantly stage I adenocarcinomas of mixed subtype exhibiting smaller dimension but greater central scar diameter and stromal invasion size in comparison with the other second-year, slower-growing adenocarcinomas. Multiple tumor nodules were identified in 10 patients exclusively at the baseline, were mostly mixed adenocarcinomas and differed in their K-ras mutation profile. Screening-detected lung cancers shared most of the histologic features of fully malignant tumors, in addition to a similar prevalence of K-ras mutations, despite their earlier detection and less advanced clinical stage. Repeat cancers are potentially aggressive tumors. K-ras mutation analysis supports the impression that multifocal tumors at baseline are separate synchronous primaries.

Methylation of O 6-methylguanine-DNA methyltransferase (MGMT) promoter gene in triple-negative breast cancer patients

Triple-negative breast cancers are characterized by the triple-negative (ER/PgR/Her2 negative) phenotype, are frequently associated with BRCA gene mutation, and are not candidate to currently available endocrine and HER2-targeted treatments. MGMT is involved in direct DNA repair exerted by cleavage of mutagenic alkyl adducts within DNA, and its epigenetic silencing confers susceptibility to DNA-damaging alkylating agents in glioblastomas and melanomas. MGMT methylation status has not been extensively investigated in breast cancer patients. The goal of our study was to evaluate the MGMT methylation status in TNBC patients, for most of which BRCA1 and BRCA2 mutational status was known. We evaluated MGMT methylation status by methylation-specific PCR (MSP) in formalin-fixed and paraffin-embedded tumor specimens from 92 TNBC patients. By using the GelDoc system (Biorad) software, the cases were further classified as follows: 0 (absence of methylated signal), 1 (prevalence of unmethylated signal, U/M ratio >1), 2 (prevalence of methylated signal, U/M ratio <1), and 3 (absence of unmethylated signal). MSP products were obtained in 89 (96.7%) of the cases. Overall, 15 (16.9%) cases were classified as 0, 33 (37.1%) cases as 1, 39 (43.8%) cases as 2, and 2 (2.2%) cases as 3. The 48 cases classified as 0 and 1 were considered as MGMT unmethylated, and the 41 cases classified as 2 and 3 as MGMT methylated. The prevalence of MGMT methylation in patients with BRCA1 mutated, wild-type, and unknown was 30.2% (13/43), 63.6% (14/22), and 58.3% (14/24), respectively. MGMT methylation was unrelated to the main clinical pathological characteristics, with the exception of a weak association with advanced age. In conclusion, our data suggest that in TNBC with wild-type BRCA1, the direct DNA repair system may be frequently (63.6%) silenced by MGMT methylation. The evaluation of the MGMT status could offer a new adjunct in predicting tumor response to alkylating drugs in TNBC patients.

The lymphoma-associated NPM-ALK oncogene elicits a p16INK4a/pRb-dependent tumor-suppressive pathway

Oncogene-induced senescence (OIS) is a barrier for tumor development. Oncogene-dependent DNA damage and activation of the ARF/p53 pathway play a central role in OIS and, accordingly, ARF and p53 are frequently mutated in human cancer. A number of leukemia/lymphoma-initiating oncogenes, however, inhibit ARF/p53 and only infrequently select for ARF or p53 mutations, suggesting the involvement of other tumor-suppressive pathways. We report that NPM-ALK, the initiating oncogene of anaplastic large cell lymphomas (ALCLs), induces DNA damage and irreversibly arrests the cell cycle of primary fibroblasts and hematopoietic progenitors. This effect is associated with inhibition of p53 and is caused by activation of the p16INK4a/pRb tumor-suppressive pathway. Analysis of NPM-ALK lymphomagenesis in transgenic mice showed p16INK4a-dependent accumulation of senescent cells in premalignant lesions and decreased tumor latency in the absence of p16INK4a. Accordingly, human ALCLs showed no expression of either p16INK4a or pRb. Up-regulation of the histone-demethylase Jmjd3 and de-methylation at the p16INK4a promoter contributed to the effect of NPM-ALK on p16INK4a, which was transcriptionally regulated. These data demonstrate that p16INK4a/pRb may function as an alternative pathway of oncogene-induced senescence, and suggest that the reactivation of p16INK4a expression might be a novel strategy to restore the senescence program in some tumors.

Gene expression profiling reveals GC and CEACAM1 as new tools in the diagnosis of lung carcinoids.

Background:Classification of lung carcinoids into typical and atypical is a diagnostic challenge since no immunohistochemical tools are available to support pathologists in distinguishing between the two subtypes. A differential diagnosis is essential for clinicians to correctly discuss therapy, prognosis and follow-up with patients. Indeed, the distinction between the two typical and atypical subtypes on biopsies/cytological specimens is still unfeasible and sometimes limited also after radical surgeries. By comparing the gene expression profile of typical (TC) and atypical carcinoids (AC), we intended to find genes specifically expressed in one of the two subtypes that could be used as diagnostic markers.Methods:Expression profiling, with Affymetrix arrays, was performed on six typical and seven atypical samples. Data were validated on an independent cohort of 29 tumours, by means of quantitative PCR and immunohistochemistry (IHC).Results:High-throughput gene expression profiling was successfully used to identify a gene signature specific for atypical lung carcinoids. Among the 273 upregulated genes in the atypical vs typical subtype, GC (vitamin D-binding protein) and CEACAM1 (carcinoembryonic antigen family member) emerged as potent diagnostic markers. Quantitative PCR and IHC on a validation set of 17 ACs and 12 TCs confirmed their reproducibility and feasibility.Conclusions:GC and CEACAM1 can distinguish between TC and AC, defining an IHC assay potentially useful for routine cytological and histochemical diagnostic procedures. The high sensitivity and reproducibility of this new diagnostic algorithm strongly support a further validation on a wider sample size.

Phase Ib of Sorafenib in Combination With Everolimus in Patients With Advanced Solid Tumors, Selected on the Basis of Molecular Targets

BACKGROUND Molecular alterations of the PI3K and Ras pathways often occur in human cancer. In this trial, the pharmacokinetics, toxicity, and activity of two drugs inhibiting these pathways-everolimus and sorafenib-were investigated. METHODS Thirteen patients with progressing solid tumors were treated with everolimus and sorafenib, according to a 3+3 scheme. Patients were selected on the basis of immunohistochemical expression of tumor molecular targets, including phospho-AKT, -p70S6K, and -ERK1/2. RESULTS The daily recommended dose identified was 2.5 mg of everolimus and 600 mg of sorafenib. Dose-limiting toxicities included grade 3 asthenia and hand-foot skin reaction. No grade 4 adverse events were observed. The most frequent grade 3 toxicities were hypophosphatemia (30.8%), alanine aminotransferase level increase, asthenia, and anorexia (14%). No pharmacokinetic interactions were identified between everolimus and sorafenib. Of 12 evaluable patients, we observed 2 partial responses, with greater than 10% shrinkage in an additional 5 patients. Objective responses were observed in one patient with a thymoma and in one patient with a lung adenocarcinoma. Tumor shrinkage that did not qualify as a partial response was seen in an abdominal leiomyosarcoma and in adenoid cystic carcinomas. CONCLUSION The combination of everolimus and sorafenib is safe. The tumor activity observed in different tumor types could be the result of the combined action of these drugs as well as the molecular selection of the treated population. Further research is warranted to better investigate drugs simultaneously blocking the PI3K and the Ras pathways and to refine patient selection.

Circulating and tissue biomarkers in early-stage non-small cell lung cancer

Objective We sought to characterise circulating and tissue tumour biomarkers of patients who developed early-stage non-small cell lung cancer (NSCLC) during long-term follow-up of a chemoprevention trial (NCT00321893). Materials and Methods Blood and sputum samples were collected from 202 high-risk asymptomatic individuals with CT-detected stable lung nodules. Real-time PCR was performed on plasma to quantify free circulating DNA. Baseline serum was investigated with a previously validated test based on 13 circulating miRNAs (miR-Test). Promoter methylation status of p16, RASSF1a and RARβ2 and telomerase activity were assessed in sputum samples. DNA was extracted from each tumour developed during follow-up and subjected to a mutation survey using the LungCarta panel on the Sequenom MassARRAY platform. Results During follow-up (9 years) six individuals underwent surgery for stage I NSCLC with a median time of disease onset of 20.5 months. MiR-Test scores were positive (range: 0.14–7.24) in four out of six baseline pre-disease onset sera. No association was identified between free circulating DNA or sputum biomarkers and disease onset. All tumours harboured at least one somatic mutation in well-known cancer genes, including KRAS (n = 4), BRAF (n = 1), and TP53 (n = 3). Conclusion Circulating miRNA tests may represent valuable tools to detect clinically-silent tumours. Early-stage lung adenocarcinomas harbour recurrent genetic events similar to those described in advanced-stage NSCLCs.