Signature-driven repurposing of Midostaurin for combination with MEK1/2 and KRASG12C inhibitors in lung cancer

Drug combinations are key to circumvent resistance mechanisms compromising response to single anti-cancer targeted therapies. The implementation of combinatorial approaches involving MEK1/2 or KRASG12C inhibitors in the context of KRAS-mutated lung cancers focuses fundamentally on targeting KRAS proximal activators or effectors. However, the antitumor effect is highly determined by compensatory mechanisms arising in defined cell types or tumor subgroups. A potential strategy to find drug combinations targeting a larger fraction of KRAS-mutated lung cancers may capitalize on the common, distal gene expression output elicited by oncogenic KRAS. By integrating a signature-driven drug repurposing approach with a pairwise pharmacological screen, here we show synergistic drug combinations consisting of multi-tyrosine kinase PKC inhibitors together with MEK1/2 or KRASG12C inhibitors. Such combinations elicit a cytotoxic response in both in vitro and in vivo models, which in part involves inhibition of the PKC inhibitor target AURKB. Proteome profiling links dysregulation of MYC expression to the effect of both PKC inhibitor-based drug combinations. Furthermore, MYC overexpression appears as a resistance mechanism to MEK1/2 and KRASG12C inhibitors. Our study provides a rational framework for selecting drugs entering combinatorial strategies and unveils MEK1/2- and KRASG12C-based therapies for lung cancer.

Whole-exome sequencing, EGFR amplification and infiltration patterns in human glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. This cancer shows rapid, highly infiltrative growth, that invades individually or in small groups the surrounding tissue. The aggressive tumor biology of GBM has devastating consequences with a median survival of 15 months. GBM often has Epidermal Growth Factor Receptor (EGFR) abnormalities. Despite recent advances in the study of GBM tumor biology, it is unclear whether mutations in GBM are related to EGFR amplification and relevant phenotypes like tumor infiltration. This study aimed to perform whole-exome sequencing analysis in 30 human GBM samples for identifying mutational portraits associated with EGFR amplification and infiltrative patterns. Our results show that EGFR-amplified tumors have overall higher mutation rates than EGFR-no-amplified. Six genes out of 2029 candidate genes show mutations associated with EGFR amplification status. Mutations in these genes for GBM are novel, not previously reported in GBM, and with little presence in the TCGA database. GPR179, USP48, and BLK show mutation only in EGFR-amplified cases, and all the affected cases exhibit diffuse infiltrative patterns. On the other hand, mutations in ADGB, EHHADH, and PTPN13, were present only in the EGFR-no-amplified group with a more diverse infiltrative phenotype. Overall, our work identified different mutational portraits of GBM related to well-established features like EGFR amplification and tumor infiltration.

Prospective analysis of liquid biopsies of advanced non-small cell lung cancer patients after progression to targeted therapies using GeneReader NGS platform

Background

In a significant percentage of advanced non-small cell lung cancer (NSCLC) patients, tumor tissue is unavailable or insufficient for genetic analyses at time to progression. We prospectively analyzed the appearance of genetic alterations associated with resistance in liquid biopsies of advanced NSCLC patients progressing to targeted therapies using the NGS platform.

Methods

A total of 24 NSCLC patients were included in the study, 22 progressing to tyrosine kinase inhibitors and two to other treatments. Liquid biopsies samples were obtained and analyzed using the GeneRead^TM QIAact Lung DNA UMI Panel, designed to enrich specific target regions and containing 550 variant positions in 19 selected genes frequently altered in lung cancer tumors. Previously, a retrospective validation of the panel was performed in clinical samples.

Results

Of the 21 patients progressing to tyrosine kinase inhibitors with valid results in liquid biopsy, NGS analysis identified a potential mechanism of resistance in 12 (57%). The most common were acquired mutations in ALK and EGFR, which appeared in 8/21 patients (38%), followed by amplifications in 5/21 patients (24%), and KRAS mutations in one patient (5%). Loss of the p.T790M was also identified in two patients progressing to osimertinib. Three of the 21 (14%) patients presented two or more concomitant alterations associated with resistance. Finally, an EGFR amplification was found in the only patient progressing to immunotherapy included in the study.

Conclusions

NGS analysis in liquid biopsies of patients progressing to targeted therapies using the GeneReader platform is feasible and can help the oncologist to make treatment decisions.

Nilotinib as Coadjuvant Treatment with Doxorubicin in Patients with Sarcomas: A Phase I Trial of the Spanish Group for Research on Sarcoma

Purpose: Nilotinib plus doxorubicin showed to be synergistic regarding apoptosis in several sarcoma cell lines. A phase I/II trial was thus designed to explore the feasibility of nilotinib as coadjuvant of doxorubicin by inhibiting MRP-1/P-gp efflux activity. The phase I part of the study is presented here.Patients and Methods: Nilotinib 400 mg/12 hours was administered in fixed dose from day 1 to 6, and doxorubicin on day 5 of each cycle. Three dose escalation levels for doxorubicin at 60, 65, and 75 mg/m² were planned. Cycles were repeated every 3 weeks for a total of 4 cycles. Eligible subtypes were retroperitoneal liposarcoma, leiomyosarcoma, and unresectable/metastatic high-grade chondrosarcoma.Results: Thirteen patients were enrolled: 7 chondrosarcoma, 4 liposarcoma, and 2 leiomyosarcoma. In 46 cycles administered, the most relevant grade 3/4 adverse effects per patient were neutropenia 54%, febrile neutropenia 15%, and asthenia 8%. No cardiac toxicity was observed. Only one dose-limiting toxicity (febrile neutropenia) was reported in the third dose level. With regard to efficacy, 1 partial response (1 liposarcoma), 9 stable diseases (5 chondrosarcoma, 2 liposarcoma, 1 leiomyosarcoma), and 3 progressive diseases (2 chondrosarcoma and 1 leiomyosarcoma) were present. ABCB1 and ABCC1 RNA expression levels decreased by 58.47-fold and 1.47-fold, respectively, on day 5 of the cycle.Conclusions: Combination of MRP-1/P-gp inhibitor, nilotinib, as coadjuvant with doxorubicin is feasible; it appears not to add substantial toxicity compared with doxorubicin alone. Pharmacodynamic study supports this concept. The recommended dose for the phase II part for doxorubicin was 75 mg/m² Clin Cancer Res; 24(21); 5239-49. ©2018 AACR.

Large scale, prospective screening of EGFR mutations in the blood of advanced NSCLC patients to guide treatment decisions

Background

In a significant percentage of advanced non-small-cell lung cancer (NSCLC) patients, tumor tissue is unavailable or insufficient for genetic analyses. We prospectively analyzed if circulating-free DNA (cfDNA) purified from blood can be used as a surrogate in this setting to select patients for treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs).

Patients and methods

Blood samples were collected in 119 hospitals from 1138 advanced NSCLC patients at presentation (n = 1033) or at progression to EGFR-TKIs (n = 105) with no biopsy or insufficient tumor tissue. Serum and plasma were sent to a central laboratory, cfDNA purified and EGFR mutations analyzed and quantified using a real-time PCR assay. Response data from a subset of patients (n = 18) were retrospectively collected.

Results

Of 1033 NSCLC patients at presentation, 1026 were assessable; with a prevalence of males and former or current smokers. Sensitizing mutations were found in the cfDNA of 113 patients (11%); with a majority of females, never smokers and exon 19 deletions. Thirty-one patients were positive only in plasma and 11 in serum alone and mutation load was higher in plasma and in cases with exon 19 deletions. More than 50% of samples had <10 pg mutated genomes/µl with allelic fractions below 0.25%. Patients treated first line with TKIs based exclusively on EGFR positivity in blood had an ORR of 72% and a median PFS of 11 months. Of 105 patients screened after progression to EGFR-TKIs, sensitizing mutations were found in 56.2% and the p.T790M resistance mutation in 35.2%.

Conclusions

Large-scale EGFR testing in the blood of unselected advanced NSCLC patients is feasible and can be used to select patients for targeted therapy when testing cannot be done in tissue. The characteristics and clinical outcomes to TKI treatment of the EGFR-mutated patients identified are undistinguishable from those positive in tumor.

Analysis of the immune microenvironment in resected non-small cell lung cancer: the prognostic value of different T lymphocyte markers

The prognosis of non-small cell lung cancer (NSCLC) remains poor and heterogeneous and new biomarkers are needed. As the immune system plays a pivotal role in cancer, the study of immune-related markers may provide valuable prognostic information of NSCLC. In 122 formalin-fixed, paraffin-embedded tumor tissue samples from early-stage NSCLC, tumor and tumor-near stromal areas were microdissected and gene expression levels of conventional and regulatory T cell markers were assessed by quantitative polymerase chain reaction. Also, the presence of infiltrating CD4+, CD8+, and FOXP3+ cells in tumor samples was assessed by immunohistochemistry. The relative proportion of conventional and regulatory T cells present in the tumor environment was assessed and found to be key to understand the importance that the immune system analysis has in the prognostics of NSCLC patients. The presence of CD8+ cells in the tumor compartment was associated with better outcome, whereas the presence of FOXP3+ cells was associated with worse overall survival. The negative prognostic value of combined biomarkers, indicating high levels of FOXP3 in the stroma and low levels of CD4 or CD8 in tumors, was observed at mRNA level and was validated by immunohistochemistry.In conclusion, the proportion of T helper and cytotoxic cells vs. regulatory T cells in different locations of the tumor microenvironment have opposite prognostic impacts in resected NSCLC.

Exosomes as diagnostic and predictive biomarkers in lung cancer

The concept of exosomes has evolved from be considered garbage bags to the demonstration that exosomes could play very interesting roles and functions, from biomarkers detection to the potential of work as drug delivery systems. It has been widely proved that exosomes can contain key molecules important for the tumour development. The current review summarizes the latest investigations developed in the field of predictive exosomal biomarkers. The microRNAs (miRNAs) are the more known molecules due to their amount inside the exosomes and the sensitivity of the techniques available for their study. However, exosomal proteins, RNA and DNA are becoming an interesting and more feasible field of study due to the improvement in the techniques available for their analysis. In the future years, it is hoped that exosomes will become an established member of the liquid biopsies in the clinical practice due to their diagnostic and prognostic properties.

Phosphorylated-insulin growth factor I receptor (p-IGF1R) and metalloproteinase-3 (MMP3) expression in advanced gastrointestinal stromal tumors (GIST). A GEIS 19 study

Background

Most GISTs have mutations in KIT or PDGFRA. Patients with advanced GIST with KIT exon 9, PDGFRA mutation or WT for KIT and PDGFRA have a worse progression-free survival (PFS) compared to patients with KIT exon 11 mutated tumors. We evaluated the immunohistochemical (IHC) expression of p-IGF1R (Y1316) and MMP3 as predictors of PFS or overall survival (OS).

Methods

Ninety-two advanced GIST patients included in GEIS-16 study with KIT and PDGFRA mutational information were examined for p-IGF1R (Y1316) and MMP3 expression in a tissue micro-array. To study activation of the IGF1R system, we have used an antibody (anti-pY1316) that specifically recognizes the active phosphorylated form of the IGF1R. DNA was extracted from paraffin-embedded tissues and intronic PCR primers were used to amplify exons 9, 11, 13 and 17 of KIT, 12 and 18 of PDGFRA. Bidirectional sequencing with specific primers was performed on a ABI3100 sequencer using the Big Dye Terminator v3.1 kit. Multivariate model was built using a stepwise automated variable selection approach with criterion to enter the variable in the model of p < 0.10 and criterion to keep the variable in the model of p < 0.05. PFS was computed as the date of imatinib initiation to progression or death. Overall survival was defined as the time from imatinib initiation to death.

Results

Phospho-IGF1R was expressed only in 9 % (2/22) of cases without KIT mutation. MMP3 expression was detected in 2/5 patients (40 %) with PDGFRA mutation, 1/16 patients (6 %) with WT genotype and 7/71 patients (10 %) of KIT mutant patients. At univariate analysis KIT exon 11/13 mutation had better PFS than patients with exon 9 mutation, PDGFRA mutation or WT genotype (p = 0.021; HR: 0.46; 95 %CI (0.28–0.76). Less than 24 months disease free-interval (HR 24.2, 95 % CI 10.5–55.8), poor performance status (PS) (HR 6.3, 95 % CI 2.5–15.9), extension of disease; >1 organ (HR 1.89; 95 % CI 1.03–3.4) and genotype analysis (HR 0.57, 95 % CI 0.37–0.97) but not immunophenotype analysis (HR 1.53; 95 % CI 0.76–3.06) were the strongest prognostic factors for PFS in the multivariate analysis.

Conclusions

Our results do not support p-IGF-1R and MMP3 evaluation in non-selected GIST patients but evaluation of this immunophenotype in WT and mutant PDGFR mutation in larger group of GIST patients, deserve merits.

Serum metabolomic profiling facilitates the non-invasive identification of metabolic biomarkers associated with the onset and progression of non-small cell lung cancer

Lung cancer (LC) is responsible for most cancer deaths. One of the main factors contributing to the lethality of this disease is the fact that a large proportion of patients are diagnosed at advanced stages when a clinical intervention is unlikely to succeed. In this study, we evaluated the potential of metabolomics by 1H-NMR to facilitate the identification of accurate and reliable biomarkers to support the early diagnosis and prognosis of non-small cell lung cancer (NSCLC).We found that the metabolic profile of NSCLC patients, compared with healthy individuals, is characterized by statistically significant changes in the concentration of 18 metabolites representing different amino acids, organic acids and alcohols, as well as different lipids and molecules involved in lipid metabolism. Furthermore, the analysis of the differences between the metabolic profiles of NSCLC patients at different stages of the disease revealed the existence of 17 metabolites involved in metabolic changes associated with disease progression.Our results underscore the potential of metabolomics profiling to uncover pathophysiological mechanisms that could be useful to objectively discriminate NSCLC patients from healthy individuals, as well as between different stages of the disease.

Abstract 4330: Immune checkpoint expression score is an independent prognostic biomarker in resectable non-small cell lung cancer

BACKGROUND

Immune checkpoints blockade, which activate antitumor immunity, has demonstrated promising clinical results in NSCLC. In this study we have investigated the prognostic role of immune checkpoint expression markers and its correlation with immune-cells infiltration and clinico-pathological characteristics in a cohort of resectable NSCLC patients.

MATERIAL AND METHODS

RNA was isolated from fresh-frozen lung specimens (tumor and normal lung) (n = 178). RTqPCR was performed to analyze the expression of CTLA-4, PD-1 and PD-L1 by the use of hydrolysis probes. Relative gene expression was assessed by Pfaffl formula and normalized by the use of CDKN1B, GUS and ACTB as endogenous genes (selected by GeNorm algorithm). These data was used to develop a gene expression score. Furthermore, the presence of CD4+, CD8+ and FOXP3+ lymphocytes was also assessed in FFPE samples from 63 of these patients by immunohistochemistry (IHC). All statistical analysis were considered significant at p&lt; 0.05.

RESULTS

Patient's median age was 65 years [26-85], 86.5% were male and 43.8% were adenocarcinomas (ADC). Since CTLA-4 and PD-1 were moderately associated with prognosis based on COX regression analysis (|Z-score|&lt;1.5), a multivariate model including these two genes was created. Absolute regression coefficients from this analysis were used in order to calculate the immune checkpoint score: (PD1 × 0.116) + (CTLA4 × 0.058) for each case. We found a significant association between the high immune checkpoint score and the presence of cytotoxic (CD8+) infiltrating lymphocytes in the tumor microenvironment (p = 0.030). Kaplan-Meier survival analysis showed that patients with high immune checkpoint score have longer overall survival (OS) [NR vs 40.4 months, p = 0.008] and longer progression free survival (PFS) [82.6 vs 23 months, p = 0.009]. A stratified analysis by histology was performed, showing a strong association between the high immune checkpoint score and better outcomes [OS p = 0.002; PFS p&lt;0.001] in the group of ADCs (n = 78). Multivariate analysis in the entire cohort indicated that the immune checkpoint score was an independent biomarker of prognosis for OS [HR: 0.308; 95%CI, 0.156-0.609; p = 0.001] and PFS [HR: 0.527; 95%CI, 0.298-0.933; p = 0.028] in early-stage NSCLC patients.

CONCLUSIONS

The immune checkpoint score based on the expression levels of CTLA-4 and PD-1 correlates with the presence of CD8+ infiltrating lymphocytes in the tumor microenvironment. This score provides relevant prognostic information for a better characterization of early-stage NSCLC patients with strikingly different outcomes who may be candidates for immune-based therapies.

Supported by grants PS09-01149 and RD12/0036/0025 from ISCIII.

Citation Format: Marta Usó, Eloisa Jantus-Lewintre, Rafael Sirera, Silvia Calabuig, Enrique Pastor, Jerónimo Forteza, Carlos Camps. Immune checkpoint expression score is an independent prognostic biomarker in resectable non-small cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4330. doi:10.1158/1538-7445.AM2015-4330

Role of surgery in patients with recurrent, metastatic, or unresectable locally advanced gastrointestinal stromal tumors sensitive to imatinib: a retrospective analysis of the Spanish Group for Research on Sarcoma (GEIS)

BACKGROUND

Recurrent, metastatic, and locally advanced gastrointestinal stromal tumors (GISTs) can be treated successfully with imatinib mesylate. Surgery for residual disease has been suggested for nonrefractory metastatic GISTs to reduce the probability of resistant recurrent clones, although no randomized Phase III trial has been performed to answer the question about its benefit. We carried out an analysis of the outcome of patients with recurrent unresectable locally advanced or metastatic imatinib-sensitive priamary GIST in 14 institutions in Spain. We compared two cohorts: treated or not treated with surgery after partial response or stabilization by imatinib.

PATIENTS AND METHODS

Data were obtained from the online GIST registry of the Spanish Group for Research in Sarcomas. Selected patients were then divided into two groups: group A, treated initially only with imatinib, and group B, treated additionally with metastasectomy. Baseline characteristics between groups were compared, and univariate and multivariate analysis for progression-free survival and overall survival (OS) were performed.

RESULTS

Analysis was undertaken in 171 patients considered nonrefractory to imatinib. The median follow-up time was 56.6 months. Focusing on OS, the Eastern Cooperative Oncology Group performance status different than 0, extent of disease limited to one metastatic organ, and comparison between groups A or B achieved statistical difference in the multivariate analysis. Median survival was 59.9 months in group A and 87.6 months in group B.

CONCLUSIONS

Based in its benefit in OS, our study supports surgery of metastatic disease in GIST patients who respond to imatinib therapy.

MRP1 overexpression determines poor prognosis in prospectively treated patients with localized high-risk soft tissue sarcoma of limbs and trunk wall: an ISG/GEIS study

Patients with localized high-risk soft tissue sarcomas (STS) of the limbs and trunk wall still have a considerable metastatic recurrence rate of more than 50%, in spite of adjuvant chemotherapy. This drug-ceiling effect of chemotherapy in sarcoma setting could be explained, at least partially, by multidrug resistance (MDR) mechanisms. The aim of this study was to ascertain whether mRNA and protein expression of ABCB1 (P-glycoprotein), ABCC1 (MRP1), and GSTA1 (glutathione S-transferase pi) was prognostic in localized high-risk STS. Immunohistochemistry and reverse transcriptase-PCR studies were performed from biopsies at the time of diagnosis. Patients of this series were prospectively enrolled into a phase III trial that compared three versus five cycles of epirubicin plus ifosfamide. The series of 102 patients found 41 events of recurrence and 37 of death with a median follow-up of 68 months. In univariate analysis, variables with a statistically significant relationship with relapse-free survival (RFS) were: MRP1 expression (5-year RFS rate of 23% in positive cases and 63% in negative cases, P = 0.029), histology (5-year RFS rate of 74% in undifferentiated pleomorphic sarcoma and 43% in synovial sarcoma, P = 0.028), and ABCC1 expression (5-year RFS rate of 33% in overexpression and 65% in downregulation, P = 0.012). Combined ABCC1/MRP1 was the only independent prognostic factor for both RFS (HR = 2.704, P = 0.005) and overall survival (HR = 2.208, P = 0.029). ABCC1/MRP1 expression shows robust prognostic relevance in patients with localized high-risk STS treated with anthracycline-based chemotherapy, which is the standard front line treatment in STS. This finding deserves attention as it points to a new targetable protein in STS.

MicroRNA profiling analysis in a series of high-risk intestinal GISTs

10532

Background: Resected localized GISTs exhibit a wide range of biological behavior from low to high risk of recurrence. Risk categories (low, intermediate and high) are built from mitotic count, size and location. However, the molecular mechanism related to GIST relapse has not yet been fully clarified. The purpose of this study is to characterize miRNA expression profile in high risk GIST patients for both, recurred and not recurred, and detect those differentially expressed in these two subsets. Methods: Twelve cases of high risk intestinal GIST, 6 with relapse and 6 without relapse, were selected for this analysis. Sections were obtained for RNA extraction using the miRNeasy FFPE kit (Qiagen) and miRNA was hybridized to the GeneChip miRNA 3.0 Array (Affymetrix) including more than 1800 human miRNA. Normalization and statistical analysis were performed with Partek Genomic Suite 6.6 software by means of ANOVA test. Fold-change (FC) and p-values were applied to generate miRNA differentially expressed lists. Results: A subset of 85 miRNA were significantly deregulated (p<0.05; FC=1.5) when comparing both groups. Among them, the highest p-values and associated FC were: mir-4776 (FC= 1,95, p= 0,011;), mir-1973 (FC= 1,59, p= 0,014) mir-4649 (FC 1,74, p= 0,028) and mir-3605 (GC= 1,58, p=0,045). All of these were up-regulated in recurred patients. Interestingly, the two samples that correspond to the biggest tumors with relapse showed a significantly different expression profile that separated them from the rest of the samples. We have identified 44 miRNAs that discriminate these two samples from the rest and show a very high statistical significance. The most significantly up regulated miRNAs were miR-100 (FC= 90,87, p<0.0001), miR-30a (FC= 156,086, p<0.0001) and down regulated miR-1184 (FC= -24,94, p<0.0001) and miR-4529 (FC= -16,61, p<0.0001). These miRNAs are involved in cell cycle and cell proliferation. Conclusions: This is the first wide characterization of miRNA profile in high risk GIST. The highest differences in expression are related to not previously described miRNAs in GIST tumors. All of them are involved in cell cycle and cell proliferation, thus expecting to regulate many GISTs associated genes, related to the relapse event.

Prognostic significance of Wnt signaling pathway molecules in nongastric GIST patients: A tissue microarray-based (TMA) analysis

10529

Background: Pathogenesis in GIST could be related to cancer stem cell hypothesis (highly chemo resistant, very uncommon complete responses, kit is stem cell marker) even though no stem cell component in GIST has been yet demonstrated. Wnt signaling regulates proliferation in some normal and cancer stem cells as it occurs with intestinal epithelium. We have explored the prognostic significance of several Wnt signaling pathway and related molecules. To investigate the prognostic significance of β-Catenin, CDC25A, ROR2, p53, CUL4A, AKT-p and VEGFR-3 by immunohistochemical (IHC) analysis in TMA specimens of 101 non-gastric GIST. Methods: Data of diagnostic, therapeutic and follow-up procedures stem from the GIST Registry of GEIS. Cytoplasmic and/or membrane staining was deemed positive for ROR-2, VEGFR-3 and p-AKT antibodies whereas nuclear staining was positive for β-Catenin, CDC25A, CUL4A and p53 antibodies. IHC positive cases were considered if they displayed staining in at least 10% of cells. Statistical analyses for correlation of protein expression with known prognostic variables (mitoses, size) were performed with Mann-Whitney U test. Results: A subset of 101 non-gastric localized GIST patients was selected (90 intestinal, 15 others: mainly rectum and omentum). The median age was 62 y with gender distribution of 59M/42F and the median of follow-up was 36 months. The positivity for each protein was distributed as follows: ROR-2 63%, p-AKT 55%, β-Catenin 53%, VEGFR-3 22%, CDC25A 20%, p53 8% and CUL4A 7%. A statistically significant correlation was found between mitoses and β-Catenin (median 5 if negative/ 10 if positive, p=0.028); VEGFR-3 (median 5 if negative/21 if positive, p=0.002); CUL4A (median 6 if negative/60 if positive, p= 0.027). Additionally, tumor size was statistically correlated with VEGFR-3 (median 7 if negative/11 if positive, p=0.007). Conclusions: VEGFR-3, β-Catenin and CUL4A are correlated with the highest proliferative non-gastric GIST. These findings deserve further analysis and lead to potential new molecular therapeutic targets in GIST. This study was partially granted by Buesa Grant of GEIS.

Relationship of CUL4A gene underexpression and prognosis in localized high-risk soft tissue sarcoma (STS) patients of limbs or trunk wall

10079

Background: Genes involved in cell cycle checkpoints and chromosome stability seem to be relevant in distant metastases appearance in STS. CUL4A is an E3 ubiquitin ligase that has been related to both p16 activation and maintenance of genomic stability. Expression of CUL4A has been scarcely described in some tumors with divergent outcome and there are no publications regarding its expression in STS patients. We previously showed that protein underexpression of CUL4A in metastatic STS was related to poor survival. Methods: The expression level of CUL4A was determined by quantitative qPCR and was retrospectively performed in a subset of 39 high-risk (grade 3, deep tumours and > than 5 cm) localized STS of limbs or trunk wall patients for which histological material and clinical data were available. Patients of this series were enrolled prospectively into a randomized clinical trial conducted by the Italian and Spanish sarcoma groups (ISG-GEIS 0101) comparing 3 vs 5 cycles of epirrubicin and ifosfamide. Differences in PFS, RFS, and OS were calculated using log-rank test Results: The median age was 51 years with a median follow-up of 52 months. The pathologic subtypes were undifferentiated pleomorphic sarcoma (35.3%), synovial sarcoma (23.5%) and mixed subtypes (41.2%). Location was distributed as inferior limbs (66.6%), upper limbs (25.5%) and trunk wall (7.9%). No relationship was seen between CUL4A expression and clinical variables (histologic types, location, size or response to neoadjuvant treatment). The expression level of CUL4A was significantly associated with events of progression, 65% vs 32%, p =0.037, for expression values under and over the median respectively. Regarding 4 y actuarial survival, there was a significant worse PFS and RFS for patients underexpressing CUL4A (p=0.041 and 0.009 respectively) and a trend towards worse OS (p=0.056). Conclusions: Expression of CUL4A gene shows a prognostic role in sarcomas within this high risk localized subset of STS patients. The outcome of this exploratory analysis is aligned with our hypothesis that genes implicated in cell cycle regulation and chromosome stability could play a relevant prognostic role in STS.

CCL27-CCR10 and CXCL12-CXCR4 chemokine ligand-receptor mRNA expression ratio: new predictive factors of tumor progression in cutaneous malignant melanoma

CXCR4, CCR7 and CCR10 chemokine receptors are known to be involved in melanoma metastasis. Our goal was to compare the relative intratumoral mRNA expression of these receptors with that of their corresponding chemokine ligands, CXCL12, CCL19, CCL21, and CCL27 across the full spectrum of human melanoma progression: thin and thick primary melanomas, as well as "in transit", lymph node, and distant metastases. Expression was quantified by real-time RT-PCR in 103 melanoma samples: 51 primary tumors and 52 metastases. Particular emphasis was focused on chemokine ligand-receptor expression ratios. Immunohistochemistry was performed to identify the cell types expressing these molecules. CXCL12-CXCR4 and CCL27-CCR10 ratios were higher in thin than in thick primary melanomas, and all four chemokine-receptor ratios were higher in primary tumors than in melanoma metastases. CCL27-CCR10 and CXCL12-CXCR4 expression ratios in primary tumors were inversely associated with the development of distant metastases, and improved the predictive value of tumor thickness for distant metastasis, which is important since chemokine ligand-receptor ratios are not affected by the endogenous gene employed for normalizing mRNA expression. Both receptor and ligand immunolabeling were detected in neoplastic cells suggesting autocrine mechanisms. Our results support the concept that low CCL27/CCR10 and CXCL12/CXCR4 intratumoral mRNA ratios are associated with melanoma progression, and in combination with Breslow thickness, are the best predictive factors for the development of distant metastases in primary cutaneous melanoma.

Análisis del gen de fusión COL1A1-PDGFB en un caso de dermatofibrosarcoma protuberans con componente de fibrosarcoma

Dermatofibrosarcoma protuberans (DFSP) is an infrequent tumor of intermediate malignancy, with little tendency to develop metastases but with a high rate of local recurrence. Cytogenetically, DFSP is characterized by a reciprocal translocation, t(17;22)(q22;q13), which is a conditioning factor in the fusion of the collagen type I alpha I gene (COL1A1) in chromosome 17q with the platelet-derived growth factor beta chain gene (PDGFB) in chromosome 22q. The fusion of these genes is variable, involving one of the 51 exons of the COL1A1 gene and exon 2 of the PDGFB gene. We present the case of a 37-year-old woman with a tumor on the arm whose histology showed a neoplastic infiltration of the subcutaneous cellular tissue made up of fusiform cells with an elongated nucleus in a storiform pattern and other more pleomorphic cells in a herringbone pattern, compatible with DFSP with a fibrosarcoma component. The molecular biology study with RT-PCR analysis of paraffin-embedded material and later sequencing showed a new fusion of exon 19 of the COL1A1 gene and exon 2 of PDGFB, supporting a diagnosis of DFSP. A study of the COL1A1-PDGFB fusion products is useful in cases where histology and immunohistochemistry are insufficient for the differential diagnosis of DFSP versus other sarcomas. It also justifies the use of new avenues of treatment with tyrosine kinase inhibitors.

Deletions affecting codons 557-558 of the c-KIT gene indicate a poor prognosis in patients with completely resected gastrointestinal stromal tumors: a study by the Spanish Group for Sarcoma Research (GEIS)

PURPOSE

To explore the prognostic value of mutations in c-KIT and PDGFR-alpha genes with respect to relapse-free survival (RFS) in patients with gastrointestinal stromal tumors (GIST). We have investigated the prognostic relevance of the type and position of the mutations, in addition to other clinicopathologic factors, in a large series of patients with GIST.

METHODS

For this study, 162 patients were selected according to the following criteria: completely resected tumors with negative margins attended between 1994 and 2001; no metastasis at diagnosis; tumor larger than 2 cm, c-KIT-positive immunostaining; and no other primary tumors.

RESULTS

The median follow-up was 42 months for patients free of recurrence. Mutations were detected in 96 tumors (60%): 82 cases involving c-KIT and 14 cases involving PDFGR-alpha. Univariate analysis demonstrated the following as poor prognostic factors for RFS: tumors larger than 10 cm (P < .0001); mitotic count higher than 10 mitoses per 50 high-power fields (P < .0001); high risk index (P < .0001); intestinal GIST location (P = .0041); high cellularity (P < .0001); tumor necrosis (P < .0001); deletions affecting exon 11 (P = .0007); and deletions affecting codons 557 to 558 (P < .0001). After the multivariate analysis, only the high risk index (relative risk [RR], 12.36), high cellularity (RR, 3.97), and deletions affecting codons 557 to 558 of c-KIT (RR, 2.57) corresponded to independent prognostic factors for RFS in GIST patients.

CONCLUSION

Deletions affecting codons 557 to 558 are relevant for the prognosis of RFS in GIST patients. This critical genetic alteration should be considered to be a new prognostic stratification variable for randomized trials exploring imatinib mesylate in the adjuvant setting in GIST patients.