The value of new high-throughput technologies for diagnosis and prognosis in solid tumors

Advances in our understanding of the molecular basis of tumors, as well as in the technology of DNA analysis, are rapidly changing the landscape of these diseases. Traditional approaches such as sequencing methods and arrays have too many limits. These have been overcome by the advent of next generation sequencing (NGS) methods which facilitate and accelerate the analysis of multiple genes and samples. These technologies allow new applications in molecular biology and medicine, for example precise analysis of RNA transcripts for gene expression; profiling of small RNAs, DNA methylation patterns and histone modification analysis; identification of splicing isoforms and of DNA regions that interact with regulatory proteins; pharmacogenomics studies and so on. In this review we describe recent applications of NGS in genomics, transcriptomics and epigenomics for a better comprehension of solid tumor metabolisms.

Proteomic profile and in silico analysis in metastatic melanoma with and without BRAF mutation

INTRODUCTION

Selective inhibitors of BRAF, vemurafenib and dabrafenib are the standard of care for metastatic melanoma patients with BRAF V600, while chemotherapy continued to be widely used in BRAF wild type patients.

MATERIALS AND METHODS

In order to discover novel candidate biomarkers predictive to treatment, serum of 39 metastatic melanoma vemurafenib (n = 19) or chemotherapy (n = 20) treated patients at baseline, at disease control and at progression, were analyzed using SELDI-TOF technology. In silico analysis was used to identify more significant peaks.

RESULTS

In patients with different BRAF status, we found 5 peptides significantly deregulated, with the down-regulation of the m/z 9176 peak strongly associated with BRAF mutation. At baseline as predictive biomarkers we identified 2 peptides - m/z 6411, 4075 - as significantly up-regulated in responders to chemotherapy and 4 peaks - m/z 5900, 12544, 49124 and 11724 - significantly up-regulated in longer vs shorter responders to vemurafenib. After response, 3 peptides (m/z 4658, 18639, and 9307) resulted significantly down regulated while 3 peptides m/z 9292, 7765 and 9176 appeared up-regulated respectively in chemotherapy and vemurafenib responder patients. In vemurafenib treated patients, 16 peaks appeared deregulated at progression compared to baseline time. In silico analysis identified proteins involved in invasiveness (SLAIN1) and resistance (ABCC12) as well as in the pathway of detoxification (NQO1) and apoptosis (RBM10, TOX3, MTEFD1, TSPO2). Proteins associated with the modulation of neuronal plasticity (RIN1) and regulatory activity factors of gene transcription (KLF17, ZBTB44) were also highlighted.

CONCLUSION

Our exploratory study highlighted some factors that deserve to be further investigated in order to provide a framework for improving melanoma treatment management through the development of biomarkers which could act as the strongest surrogates of the key biological events in stage IV melanoma.

Combined microRNA and ER expression: a new classifier for familial and sporadic breast cancer patients

BACKGROUND

The role of miRNAs in familial breast cancer (fBC) is poorly investigated as also in the BRCA-like tumors. To identify a specific miRNA expression pattern which could allow a better fBC classification not only based on clinico-pathological and immunophenotypical parameters we analyzed miRNA profile in familial and sporadic samples. Moreover since BRCA1 tumors and sporadic triple negative (TN) breast tumors share similarities regarding clinical outcomes and some histological characteristics, we focused on TN and not TN cases.

METHODS

The sample set included fresh frozen tissue samples, including 39 female fBCs (19 BRCA-related and 20 BRCAX) and 12 male fBC (BRCAX). Moreover, we considered TN and non TN (NTN), 21 BRCA-related and 27 sporadic BCs. MiRNA profiling was performed through GeneChip miRNA v.1.0 Array (Affymetrix). ANOVA, hierarchical and consensus clustering analyses allowed identification of pattern of expression of miRNAs and pathway enrichment analysis, considering validated target genes, was carried out to achieve a deeper biological understanding.

RESULTS

ANOVA test led to the identification of 53 deregulated miRNAs; hierarchical and consensus clustering of female fBCs (fFBCs) and male fBCs (fMBCs) highlighted the presence of 3 sample clusters named FBC1, FBC2 and FBC3. We found a correlation between ER-status and the three sample clusters. The three clusters are distinct by a different expression of two clusters of miRNAs (CLU1 and CLU2), which resulted to be different in targeted pathways. In particular, CLU1 targets cellular pathways and CLU2 is involved in epigenetic activities. Considering TN and NTN BRCA-related and sporadic tumors, a hierarchical clustering identified two clusters of miRNAs, which were not so different from CLU1 and CLU2, both in miRNA content and targeted pathways.

CONCLUSIONS

Our results highlighted the importance of miRNA regulation to better clarify similarities and differences between familial and sporadic BC groups.

HOX gene methylation status analysis in patients with hereditary breast cancer

Cancer development is related not only to genetic alterations but also to aberrant epigenetic changes that could lead to heritable gene patterns critical for neoplastic initiation and progression. Knowledge of epigenetic regulation in cancer cells is useful for both the understanding of carcinogenesis and for the possibility of using epigenetic drugs. HOX genes deregulation have a crucial role in oncogenesis process and tumor suppression. In this report, the methylation of HOXA1, HOXA9, HOXA10, HOXB13, HNF1B, OTX1, TLX1 genes have been analyzed in patients with hereditary breast cancer. This is the first study analyzing BRCA mutational status of patients with respect to methylation of HOX genes. HOXA10 has been found to be methylated in all patients analyzed but never in healthy subjects. With respect to clinical pathological information, hypermethylation of all studied genes, with the exception of OTX1, was significantly associated with absence of HER2 neu expression (P<0.05). Moreover, hypermethylation of HOXB13, HOXA10 and HOXA1 was associated with a high proliferation index (Mib1≥10%, P<0.05) and hypermethylation of HOXB13 and HOXA10 also with high expression of estrogen and progesterone receptors. These preliminary data suggest a possible involvement of HOX genes in familial breast cancer as marker helpful to identify high-risk patients.