ANKRD44 Gene Silencing: A Putative Role in Trastuzumab Resistance in Her2-Like Breast Cancer

Trastuzumab is an effective therapeutic treatment for Her2-like breast cancer; despite this most of these tumors develop resistance to therapy due to specific gene mutations or alterations in gene expression. Understanding the mechanisms of resistance to Trastuzumab could be a useful tool in order to identify combinations of drugs that elude resistance and allow a better response for the treated patients. Twelve primary biopsies of Her2+/hormone receptor negative (ER-/PgR-) breast cancer patients were selected based on the specific response to neoadjuvant therapy with Trastuzumab and their whole exome was sequenced leading to the identification of 18 informative gene mutations that discriminate patients selectively based on response to treatment. Among these genes, we focused on the study of the ANKRD44 gene to understand its role in the mechanism of resistance to Trastuzumab. The ANKRD44 gene was silenced in Her2-like breast cancer cell line (BT474), obtaining a partially Trastuzumab-resistant breast cancer cell line that constitutively activates the NF-kb protein via the TAK1/AKT pathway. Following this activation an increase in the level of glycolysis in resistant cells is promoted, also confirmed by the up-regulation of the LDHB protein and by an increased TROP2 protein expression, found generally associated with aggressive tumors. These results allow us to consider the ANKRD44 gene as a potential gene involved in Trastuzumab resistance.

Laser Capture Microdissection and RNA-Seq Analysis: High Sensitivity Approaches to Explain Histopathological Heterogeneity in Human Glioblastoma FFPE Archived Tissues

Laser capture microdissection (LCM) coupled with RNA-seq is a powerful tool to identify genes that are differentially expressed in specific histological tumor subtypes. To better understand the role of single tumor cell populations in the complex heterogeneity of glioblastoma, we paired microdissection and NGS technology to study intra-tumoral differences into specific histological regions and cells of human GBM FFPE tumors. We here isolated astrocytes, neurons and endothelial cells in 6 different histological contexts: tumor core astrocytes, pseudopalisading astrocytes, perineuronal astrocytes in satellitosis, neurons with satellitosis, tumor blood vessels, and normal blood vessels. A customized protocol was developed for RNA amplification, library construction, and whole transcriptome analysis of each single portion. We first validated our protocol comparing the obtained RNA expression pattern with the gene expression levels of RNA-seq raw data experiments from the BioProject NCBI database, using Spearman's correlation coefficients calculation. We found a good concordance for pseudopalisading and tumor core astrocytes compartments (0.5 Spearman correlation) and a high concordance for perineuronal astrocytes, neurons, normal, and tumor endothelial cells compartments (0.7 Spearman correlation). Then, Principal Component Analysis and differential expression analysis were employed to find differences between tumor compartments and control tissue and between same cell types into distinct tumor contexts. Data consistent with the literature emerged, in which multiple therapeutic targets significant for glioblastoma (such as Integrins, Extracellular Matrix, transmembrane transport, and metabolic processes) play a fundamental role in the disease progression. Moreover, specific cellular processes have been associated with certain cellular subtypes within the tumor. Our results are promising and suggest a compelling method for studying glioblastoma heterogeneity in FFPE samples and its application in both prospective and retrospective studies.

Molecular profiling of microinvasive breast cancer microenvironment progression

Background

Tumors develop by progression through a series of stages. Every cell of the tumor microenvironment is constantly changing in the flow of the cancer progression. It has become clear in recent years that stroma is essential for tumor maintenance and growth. Here, we aimed to give a chronological order of gene expression changes given in the dynamical framework of microinvasive breast cancer microenvironment.

Methods

RNA-seq was performed on seven microinvasive breast cancers. For each of them we microdissected seven different portions of the tumor, four related to the breast epithelium and three to the stroma. Breast epithelium was chronologically subdivided in normal breast epithelium (NBE), carcinoma in situ (CIS), emerging invasive fingers (EIF) and invasive breast cancer (IBC). For each of the breast epithelium subdivisions we collected the adjacent stroma (S): S-NBE, S-EIF and S-IBC.

Results

The overall differentially expressed genes (DEGs) in all the compartments were analysed and evaluated to understand the pathways involved in tumor progression. Then we analysed the DEGs of the epithelial and stromal portions in comparison with the normal portions. We observed that the stromal cells are necessary for the development and the maintenance of the tumor, especially in tumor progression. Moreover the most important genes involved in the main metabolic pathways were analysed and the communications within the different cell compartments were highlighted.

Conclusions

As a future perspective, a deeply study of the identified key genes, particularly in the stromal cells, will be crucial to develop an anticancer therapy that is undergoing a conversion from a cancer cell-centric strategy to a stroma-centric strategy, more genomically stable.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1936-x) contains supplementary material, which is available to authorized users.

Molecular characterization of low grade and high grade bladder cancer

Background

Bladder cancer (BC) is the 9^th most common cancer diagnosis worldwide. Low grade (LG) represents 70% of all BCs, characterized by recurrence and rare ability (10–15%) to progress to high grade (HG) and invade. The remaining 30% is high grade (HG), fast invasive BC, which is resistant to therapy. Identifying biomarkers for predicting those tumors able to progress is a key goal for patient outcome improvement. This study focuses on the most promising prognostic markers.

Materials and methods

TP53 and FGFR3 mutational status, Survivin, CK19, CK20, E-cadherin and CD44 gene expression analysis were performed on 66 BCs.

Results

Survivin was found associated to tumor grade (p<0.05). Moreover, Survivin correlated with CD44 in TP53 wild type (p = 0.0242) and FGFR3 wild type (p = 0.0036) tumors. In particular the Survivin-CD44 correlation was associated to HG FGFR3 wild type BCs (p = 0.0045). Unsupervised hierarchical clustering based on gene expression data identified four distinct molecular groups reflecting the patient histology (p = 0.038).

Conclusion

We suggest Survivin, both as a biomarker associated to G3 BCs but negatively related to TP53 mutational status, and as a potential novel therapeutic target.

Mouse mammary tumour virus-like env nucleotide and p14 signal peptide are present in feline mammary carcinomas, but not in neoplastic or dysplastic canine mammary lesions

Mouse mammary tumour virus-like (MMTV-like) is suspected to be involved in human breast cancer and it has been hypothesized that companion animals might have a role in viral transmission. The aim of our study was to investigate the presence of MMTV-like nucleotide sequences and viral protein in a larger number of feline (FMCs) and canine mammary carcinomas (CMCs) by nested PCR and immunohistochemistry. Results showed that the presence of MMTV-like env sequence in FMCs was 7% (6/86), while all the CMCs and canine dysplastic lesions scored negative. All PCR-positive FMCs scored positive for the MMTV p14 signal peptide of the envelope precursor protein of the virus. In contrast, all PCR-negative FMCs and canine mammary lesions were also negative for immunohistochemistry analysis. Canine and feline normal mammary gland tissues scored negative for both PCR and MMTV-p14 protein. Multiple nucleotide alignment of MMTV-like env gene sequences isolated from cat showed 97% and 99% similarity with HMTV and MMTV, respectively, while the others two presented some polimorphisms. Particularly the sequences of one of these two tumors showed a polymorphism (c.7575 A> G), that causes a previously unreported amino acid substitution (Thr > Ala). In conclusion, the results of our study showed the presence of MMTV-like sequences and viral protein in some FMCs. Further studies are needed to understand whether this virus does play a role in the development of FMCs, if MMTV-like is an exogenous virus as these data suggest and, in such a case, how and from whom this virus was acquired.

Next generation sequencing technologies for a successful diagnosis in a cold case of Leigh syndrome

Background

Leigh Syndrome (LS, OMIM 256000) is an early-onset, progressive neurodegenerative disorder characterized by broad clinical and genetic heterogeneity; it is the most frequent disorder of mitochondrial energy production in children. LS inheritance is complex because patients may present mutations in mitochondrial DNA (mtDNA) or in nuclear genes, which predominantly encode proteins involved in respiratory chain structure and assembly or in coenzyme Q10 biogenesis. However, during the last 15 years, the discovery of several genetic mutations and improved knowledge of the natural history of LS has significantly increased our understanding of this mitochondrial disorder.

Case presentation

Here we describe a 19-year-old male with clinical and neuroimaging LS diagnosed at 3 years of age. Genetic analyses of the whole mtDNA for maternally inherited LS (MILS) and neuropathy ataxia retinitis pigmentosa (NARP) syndrome failed to reveal any pathogenic mutations.

Conclusions

Recently, a missense mutation in ECHS1 and a ~ 35 kb deletion in 10q26.3 involving the region including the gene were identified by WES (whole exome sequencing), uncovering the genetic diagnosis clinically hypothesized for 15 years. We also report the long-term follow-up of this patient, showing a comparison with classical LS or other Leigh-like pictures.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1103-7) contains supplementary material, which is available to authorized users.

Levels of miR-126 and miR-218 are elevated in ductal carcinoma in situ (DCIS) and inhibit malignant potential of DCIS derived cells

A substantial number of ductal carcinoma in situ (DCIS) detected by mammography never progress to invasive ductal carcinoma (IDC) and current approaches fail to identify low-risk patients not at need of adjuvant therapies. We aimed to identify the key miRNAs protecting DCIS from malignant evolution, that may constitute markers for non-invasive lesions. We studied 100 archived DCIS samples, including pure DCIS, DCIS with adjacent IDC and pure DCIS from patients with subsequent IDC in contralateral breast or no recurrence. A DCIS derived cell line was used for molecular and cellular studies. A genome wide study revealed that pure DCIS has higher miR-126 and miR-218 expression than DCIS with adjacent IDC lesions or than IDC. The down-regulation of miR-126 and miR-218 promoted invasiveness in vitro and, in patients with pure DCIS, was associated with later onset of IDC. Survival studies of independent cohorts indicated that both miRNAs play a protective role in IDC. The clinical findings are in agreement with the miRNAs' roles in cell adhesion, differentiation and proliferation. We propose that miR-126 and miR-218 have a protective role in DCIS and represent novel biomarkers for the risk assessment in women with early detection of breast cancer.

CXCL12α/SDF-1 from perisynaptic Schwann cells promotes regeneration of injured motor axon terminals

The neuromuscular junction has retained through evolution the capacity to regenerate after damage, but little is known on the inter-cellular signals involved in its functional recovery from trauma, autoimmune attacks, or neurotoxins. We report here that CXCL12α, also abbreviated as stromal-derived factor-1 (SDF-1), is produced specifically by perisynaptic Schwann cells following motor axon terminal degeneration induced by α-latrotoxin. CXCL12α acts via binding to the neuronal CXCR4 receptor. A CXCL12α-neutralizing antibody or a specific CXCR4 inhibitor strongly delays recovery from motor neuron degeneration in vivo Recombinant CXCL12α in vivo accelerates neurotransmission rescue upon damage and very effectively stimulates the axon growth of spinal cord motor neurons in vitro These findings indicate that the CXCL12α-CXCR4 axis plays an important role in the regeneration of the neuromuscular junction after motor axon injury. The present results have important implications in the effort to find therapeutics and protocols to improve recovery of function after different forms of motor axon terminal damage.

A new immunization and treatment strategy for mouse mammary tumor virus (MMTV) associated cancers

Mouse Mammary Tumor Virus (MMTV) causes mammary carcinoma or lymphoma in mice. An increasing body of evidence in recent years supports its involvement also in human sporadic breast cancer. It is thus of importance to develop new strategies to impair the development, growth and metastasis of MMTV-associated cancers. The signal peptide of the envelope precursor protein of this virus: MMTV-p14 (p14) is an excellent target for such strategies, due to unique characteristics distinct from its regular endoplasmic reticulum targeting function. These include cell surface expression in: murine cancer cells that harbor the virus, human breast cancer (MCF-7) cells that ectopically express p14, as well as cultured human cells derived from an invasive ductal breast carcinoma positive for MMTV sequences. These findings support its use in signal peptide-based immune targeting. Indeed, priming and boosting mice with p14 elicits a specific anti-signal peptide immune response sufficient for protective vaccination against MMTV-associated tumors. Furthermore, passive immunization using a combination of anti-p14 monoclonal antibodies or the transfer of T-cells from immunized mice (Adoptive Cell Transfer) is also therapeutically effective. With reports demonstrating involvement of MMTV in human breast cancer, we propose the immune-mediated targeting of p14 as a strategy for prevention, treatment and diagnosis of MMTV-associated cancers.

Whole-exome analysis in osteosarcoma to identify a personalized therapy

Osteosarcoma is the most common pediatric primary non-hematopoietic bone tumor. Survival of these young patients is related to the response to chemotherapy and development of metastases. Despite many advances in cancer research, chemotherapy regimens for osteosarcoma are still based on non-selective cytotoxic drugs. It is essential to investigate new specific molecular therapies for osteosarcoma to increase the survival rate of these patients. We performed exomic sequence analyses of 8 diagnostic biopsies of patients with conventional high grade osteosarcoma to advance our understanding of their genetic underpinnings and to correlate the genetic alteration with the clinical and pathological features of each patient to identify a personalized therapy. We identified 18,275 somatic variations in 8,247 genes and we found three mutated genes in 7/8 (87%) samples (KIF1B, NEB and KMT2C). KMT2C showed the highest number of variations; it is an important component of a histone H3 lysine 4 methyltransferase complex and it is one of the histone modifiers previously implicated in carcinogenesis, never studied in osteosarcoma. Moreover, we found a group of 15 genes that showed variations only in patients that did not respond to therapy and developed metastasis and some of these genes are involved in carcinogenesis and tumor progression in other tumors. These data could offer the opportunity to get a key molecular target to identify possible new strategies for early diagnosis and new therapeutic approaches for osteosarcoma and to provide a tailored treatment for each patient based on their genetic profile.

Whole-exome analysis of a Li-Fraumeni family trio with a novel TP53 PRD mutation and anticipation profile

Li-Fraumeni syndrome is a clinically heterogeneous familial cancer predisposition syndrome with autosomal-dominant inheritance caused by heterozygous germline mutations in the TP53 gene. We here analyze the genetic background of a family with a 4-year-proband presented with a Li-Fraumeni tumor. The mother developed breast cancer at age 37 and the proband died at age 8. We performed Sanger sequencing and whole-exome sequencing on peripheral blood DNA from proband and relatives. Data analysis selected only high-quality score and depth reads, rare variants and protein impact involving missense, non-sense, frameshift and splice disrupt mutations. Disease implicated variants and predicted deleterious alterations were also chosen. TP53 genetic testing revealed a never reported TP53 deletion arose as de novo mutation in the mother and inherited by the proband. We then performed whole-exome analysis of the trio to uncover inherited variants from the father that potentially worsen the already altered genetic background in the proband. No pathogenic variants were inherited in autosomal recessive, de novo dominant or X-linked recessive manner. Comparing proband and father exome we detected 25 predicted deleterious variants including a nonsense mutation in ERCC3. Those inherited mutations are possible candidate modifiers linked to TP53, explaining the proband accelerated tumor onset compared to the mother and providing a possible explanation of the genetic anticipation event in this Li-Fraumeni family.

Loss of c-KIT expression in thyroid cancer cells

Papillary thyroid carcinoma is the most frequent histologic type of thyroid tumor. Few studies investigated the role of c-KIT expression in thyroid tumors, suggesting a role for this receptor and its ligand in differentiation and growth control of thyroid epithelium and a receptor loss following malignant transformation. We investigated and correlated c-KIT expression levels and two known markers of thyrocytes differentiation, PAX8 and TTF-1, in malignant and benign cytological thyroid samples. Moreover, we performed functional studies on human papillary thyroid carcinoma cell line to associated c-KIT expression to thyrocytes differentiation and tumor proliferation. c-KIT and PAX8 expression resulted higher in benign samples compared to the malignant ones, and the expression levels of these two genes were significantly correlated to each other. We also observed that c-KIT overexpression led to an increase of PAX8 expression level together with a decrease of proliferation. Furthermore, c-KIT overexpressing cells showed a regression of typical morphological features of malignancy. Taken together these results suggest that c-KIT could be involved in the differentiation of thyroid cells and in tumor progression.

Micro-RNA-21 (biomarker) and global longitudinal strain (functional marker) in detection of myocardial fibrotic burden in severe aortic valve stenosis: a pilot study

Aims

Myocardial fibrosis (MF) is a deleterious consequence of aortic valve stenosis (AVS). Global longitudinal strain (GLS) is a novel left ventricular (LV) functional parameter potentially useful to non-invasively estimate MF. MicroRNAs (miRNAs) are non-coding small ribonucleic acids (RNA) modulating genes function, mainly through RNA degradation. miRNA-21 is a biomarker associated with MF in pressure overload. The aim of the present study was to find an integrated algorithm for detection of MF using a combined approach with both bio- and functional markers.

Methods

Thirty-six patients (75.2 ± 8 y.o.; 63 % Female) with severe AVS and preserved LV ejection fraction (EF), candidate to surgical aortic valve replacement (sAVR) were enrolled. Clinical, bio-humoral evaluation (including plasmatic miRNA-21 collected using specific tubes, PAXgene, for stabilization of peripheral RNA) and a complete echocardiographic study, including GLS and septal strain, were performed before sAVR. Twenty-eight of those patients underwent sAVR and, in 23 of them, an inter-ventricular septum biopsy was performed. Tissues were fixed in formalin and embedded in paraffin. Sections were stained with Hematoxylin and Eosin for histological evaluation and with histochemical Masson trichrome for collagen fibers. The different components were calculated and expressed as micrometers². To evaluate tissue miRNA components, sections 2-μm thick were cut using a microtome blade for each slide. Regression analysis was performed to test association between dependent variable and various predictors included in the model.

Results

Despite a preserved EF (66 ± 11 %), patients presented altered myocardial deformation parameters (GLS −14,02 ± 3.8 %; septal longitudinal strain, SSL −9.63 ± 2.9 %; septal longitudinal strain rate, SL-Sr −0.58 ± 0.17 1/s; Septal Longitudinal early-diastolic strain rate, SL-SrE 0.62 ± 0.32 1/s). The extent of MF showed an inverse association with both GLS and septal longitudinal deformation indices (GLS: R² = 0.30; p = 0.02; SSL: R² = 0.36; p = 0.01; SL-Sr: R² = 0.39; p < 0.001; SL-SrE: R² = 0.35; p = 0.001). miRNA-21 was mainly expressed in fibrous tissue (p < 0.0001). A significant association between MF and plasmatic miRNA-21, alone and weighted for measures of structural (LVMi R² = 0.50; p = 0.0005) and functional (SSL R² = 0.35; p = 0.006) remodeling, was found.

Conclusions

In AVS, MF is associated with alterations of regional and global strain. Plasmatic miRNA-21 is directly related to MF and associated with LV structural and functional impairment.

Abstract P1-03-07: The "panta rhei" of breast cancer: Gene expression timeline analysis during progression of microinvasive breast cancer microenvironment

Background. Tumors develop by progression through a series of stages. It is now widely accepted that cancer is attributed to the accumulation of genetic alterations in cells. Every cells of the tumor microenvironment is constantly changing in the flow of the cancer progression. A number of genes have been identified as having functions in various stages of progression in promoting cancer progression in experimental models. However, the association between gene expression alterations and resulting phenotypic alterations with respect to the aggressiveness and migration potential of cancer cells is not fully understood. Therefore, elucidation of genotype–phenotype correlation will be required to further understand the complex process of progression and invasion. All tumors require at least some stroma to meet their needs of nutrition, waste removal, and structure. It has become clear in recent years that stroma is essential for tumor maintenance and growth and has potential as a therapeutic target. Here, we aimed to give a chronological order of gene expression changes given in the dynamical framework of microinvasive breast cancer microenvironment.

Materials and Methods. RNA-seq (Ion Proton technology) was performed on three microinvasive breast cancers, applying new modifications to the usual protocol. For each of them we microdissected 7 different portions of the tumor (around 200 cells), 4 related to the breast epithelium and 3 to the stroma. The regions were selected on the basis of their grade of progression. Breast epithelium was chronologically subdivided in normal breast epithelium (NBE), carcinoma in situ (CIS), emerging invasive fingers (EIF) and invasive breast cancer (IBC). For each of the breast epithelium subdivisions we collected the adjacent stroma (S) except for the in situ portion: S-NBE, S-EIF and S-IBC.

Results: Whole transcriptome analysis performed on each microdissected regions reveals a series of gene expression changes occurring during cancer progression in the breast epithelium along with the adjacent stroma. The dendogram analysis, based on the whole gene expression data of each patient revealed a perfect group organization of the various microdissected portions of stroma and mammary epithelium. Within the dendogram, the organization of Normal, In Situ, EIF and Invasive tissue respected perfectly the biological assumptions.

Conclusions: More thorough analyses are needed to give a clear view of the flow of molecular events starting from the normal breast epithelium to the microinvasive stage, as well as to give a better understanding of the stroma-epithelium molecular means of communication. The analysis of all the molecular changes occuring in the breast epithelium and in the stroma of microinvasive cancer could lead to the development of new therapeutic targets.

Citation Format: Lessi F, Scatena C, Aretini P, Menicagli M, Franceschi S, Ortenzi V, La Ferla M, De Gregorio V, Bevilacqua G, Naccarato GA, Mazzanti CM. The "panta rhei" of breast cancer: Gene expression timeline analysis during progression of microinvasive breast cancer microenvironment. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-03-07.

Investigating molecular alterations to profile short- and long-term recurrence-free survival in patients with primary glioblastoma

Glioblastoma (GB) is the most aggressive type of primary brain tumor. Despite the progress in recent years regarding the diagnosis and treatment of GB, the recurrence rate remains high, due to the infiltrative and dispersive nature of the tumor, which typically results in poor patient prognosis. In the present study, 19 formalin-fixed, paraffin-embedded GB samples were selected from patients with GB tumors. The samples were classified into a short or long recurrence-free survival (RFS) group, based on the time of first recurrence of the disease in the patients. The 19 samples were molecularly characterized for mutations in the isocitrate dehydrogenase 1 (IDH1) gene, amplification of the epidermal growth factor receptor (EGFR) gene, presence of the EGFR variant III, and methylation of the promoter region of the O⁶-methylguanine-DNA methyltransferase (MGMT) gene. Then, the expression of 84 genes involved in cell-cell and cell-matrix interactions, and that of 84 microRNAs (miRNAs) associated with brain cancer, was profiled. In addition, a copy number variation analysis of 23 genes reported to undergo frequent genomic alterations in human glioma was also performed. Differences in the expression levels of a number of genes were detected across the short and long RFS groups. Among these genes, 5 in particular were selected, and a 5-genes combination approach was developed, which was able to differentiate between patients with short and long RFS outcome. The high levels of sensitivity and precision displayed by this 5-genes combination approach, which were confirmed with a cross-validation method, provide a strong foundation for further validation of the involvement of the aforementioned genes in GB in a larger patient population. In conclusion, the present study has demonstrated how the expression pattern of miRNAs and mRNAs in patients with GB defines a particular molecular hallmark that may increase or reduce the aggressive behavior of GB tumors, thus influencing the survival rates of patients with GB, their response to therapy and their tendency to suffer a relapse.

Abstract 1120: Glioblastoma whole transcriptome analysis: molecular mechanisms related to recurrence-free survival (RFS)

Introduction. Diffusely infiltrating astrocytomas represent the most frequent intracranial neoplasms, with the glioblastoma (GB) as the most malignant phenotypic endpoint. Surgical resection, radiotherapy and adjuvant chemotherapy currently represent the standard of care for this disease. From a practical perspective, controlling growth and spreading of the recurrence may have a great impact on disease-free survival. The invasive nature of glioblastoma cells represents a major cause of therapeutic failure, so clarification of the molecular mechanisms associated with cellular migration and invasion is crucial to allow better prediction of these patient. Our study had the intent to provide novel information on glioblastoma behavior, with regard to the type of genetic changes involved in length of recurrence free survival time.

Materials and Methods. We used whole-transcriptome RNA sequencing (Ion Proton system) to analyze 12 primary formalin fixed, paraffin embedded GBs specifically selected for different length of time of first recurrence.

Results. A total of 83 genes resulted to have a statistical significant differential expression, which allowed us to distinguish three distinct groups of tumors with different recurrence free survival times: the short term group (S) with recurrence free survival time less than 6 months (n = 6), the medium group (M) between 16 and 23 months (n = 3), and the long term group (L) with more than 25 months (n = 3). Gene expression comparison analysis identified 51, 21, 26 significant genes between L/S, L/M and S/M respectively. Interestingly the highest number of genes differentialy expressed was found between the two extreme groups (S vs L). Two genes, BOD1L1 and GLUD2 were identified as significantly upregulated in the L group.

Conclusions. The analysis of the whole transcriptome of GBs, with different recurrence free survival time, revealed that many of the genes that seem to be related to time of recurrence, after first surgery, are involved in the epigenetic landscape of the transcriptional potential of the cell such as histone and miRNA expression dis-regulation. Two genes were confirmed such as BOD1L1, which is mostly unknown and seems to be involved in the bio-orientation of chromosomes, and the mitochondrial enzyme GLUD2 which has been recently reported as involved in glioma growth. Moreover, some of the upregulated genes, in the group with the worst prognosis, had been related to the Rho family of GTPases which are key mediators of GB invasion. More thorough analyses are ongoing. A comprehensive better understanding of the molecular mechanisms underlying GB recurrence free survival would make a long step forward in the improvement of the clinical management of patients with such deadly disease.

Citation Format: Sara Franceschi, Francesca Lessi, Paolo Aretini, Francesco G. Carbone, Cristian Scatena, Marco La Ferla, Valerio Ortenzi, Riccardo Vannozzi, Generoso Bevilacqua, Antonio G. Naccarato, Chiara M. Mazzanti. Glioblastoma whole transcriptome analysis: molecular mechanisms related to recurrence-free survival (RFS). [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 1120. doi:10.1158/1538-7445.AM2015-1120

VHL and HIF-1α: gene variations and prognosis in early-stage clear cell renal cell carcinoma

Von Hipple-Lindau gene (VHL) inactivation represents the most frequent abnormality in clear cell renal cell carcinoma (ccRCC). Hypoxia-inducible factor-1α (HIF-1α) expression is regulated by O2 level. In normal O2 conditions, VHL binds HIF-1α and allows HIF-1α proteasomal degradation. A single-nucleotide polymorphism (SNP) has been found located in the oxygen-dependent degradation domain at codon 582 (C1772T, rs11549465, Pro582Ser). In hypoxia, VHL/HIF-1α interaction is abolished and HIF-1α activates target genes in the nucleus. This study analyzes the impact of genetic alterations and protein expression of VHL and the C1772T SNP of HIF-1α gene (HIF-1α) on prognosis in early-stage ccRCC (pT1a, pT1b, and pT2). Mutational analysis of the entire VHL sequence and the genotyping of HIF-1α C1772T SNP were performed together with VHL promoter methylation analysis and loss of heterozygosis (LOH) analysis at (3p25) locus. Data obtained were correlated with VHL and HIF-1α protein expression and with tumor-specific survival (TSS). VHL mutations, methylation status, and LOH were detected in 51, 11, and 12% of cases, respectively. Our results support the association between biallelic alterations and/or VHL silencing with a worse TSS. Moreover, we found a significant association between the HIF-1α C1772C genotype and a worse TSS. The same association was found when testing the presence of HIF-1α protein in the nucleus. Our results highlight the role of VHL/HIF-1α pathway in RCC and support the molecular heterogeneity of early-stage ccRCC. More important, we show the involvement of HIF-1α C1772T SNP in ccRCC progression.