Search

NTRODUCTION: Circulating tumor cells are thought to play a crucial role in the development of distant metastases. Their detection in the blood of colorectal cancer patients may be linked to poor outcome, but current evidence is controversial. MATERIALS AND METHODS: Pre- and postoperative flow cytometric analysis of blood samples was carried out in 76 colorectal cancer patients undergoing surgical resection. The EpCAM/CD326 epithelial surface antigen was used to identify circulating tumor cells. RESULTS: Fifty-four (71%) patients showed circulating tumor cells preoperatively, and all metastatic patients showed high levels of circulating tumor cells. Surgical resection resulted in a significant decrease in the levels of circulating tumor cells. Among 69 patients undergoing radical surgery, 16 had high postoperative levels of circulating tumor cells, and 12 (75%) experienced tumor recurrence. High postoperative level of circulating tumor cells was the only independent variable related to cancer relapse. In patients without circulating tumor cells, the progression-free survival rate increased from 16 to 86%, with a reduction in the risk of tumor relapse greater than 90%. CONCLUSIONS: High postoperative levels of circulating tumor cells accurately predicted tumor recurrence, suggesting that assessment of circulating tumor cells could optimize tailored management of colorectal cancer patients.

Colorectal cancer (CRC) is one of the most common types of cancer; it is diagnosed in more than one million people each year and causes the death of about half of them. Early detection can help to decrease CRC-related mortality. In fact, the 5-year survival rate exceeds 90 % when the disease is localized and is only 10 % in case of metastases. Consequently, it is imperative to improve methods for the early detection of the disease. In this context, genomic approaches have resulted in new CRC biomarkers and have helped to shed light on the genetic basis of cancer as a whole. However, the proteome provides a more dynamic and faithful image of the genetic program of a cell. Hence, given the importance of proteins as effectors of cellular behavior, proteomic analysis has the potential to identify biomarkers that can help to classify and predict CRC. Several proteomic technique, such as matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), quantitative isotopic protein labeling (SILAC, ICAT, and iTRAQ), and two-dimensional gel electrophoresis (2D-PAGE and 2D-DIGE), are being used in cancer research and can improve the diagnosis of patients; they are also helping to optimize personalized therapy. In this chapter, the main proteomic approaches used in biomarker research will be discussed, together with their impact and potential in the clinical setting. The proteomic biomarkers currently used for CRC diagnosis and/or therapy monitoring will be also described. List of Abbreviations 2D-DIGE Two-Dimensional Differential In-gel Electrophoresis 2D-PAGE Two-Dimensional Polyacrylamide Gel Electrophoresis APC Adenomatous Polyposis Coli CEA Carcinoembryonic Antigen CRC Colorectal Cancer Cy2 Cyanine 2 Fluorescent Dye Cy3 Cyanine 3 Fluorescent Dye Cy5 Cyanine 5 Fluorescent Dye DCBE Double-Contrast Barium Enema ESI Electrospray Ionization FIT Fecal Immunological Test FOBT Fecal Occult Blood Test *Email: salvator@unina.it Biomarkers in Cancer DOI 10.1007/978-94-007-7744-6_16-1 # Springer Science+Business Media Dordrecht 2014

The cancer stem cell (CSC) theory represents a breakthrough in cancer research. We characterized the protein pattern of CSCs to identify specific intracellular pathways in this subpopulation of tumor cells. We studied colon CSCs using two different colon cancer cell lines: CaCo-2 and HCT- 116. Putative CSCs were separated from non-CSCs by flow cytometry using CD133 as stemness marker. Total protein extracts of CD133+ cells were then compared to protein extracts of CD133- cells by 2D DIGE. The protein spots differentially expressed in the two subpopulation of cells were analyzed by mass spectrometry. Bioinformatics analysis of the identified proteins indicated alteration of two main processes: energy metabolism and the Wnt pathway. Interestingly, we observed up-regulation of the splicing factor SRp20, a newly identified target gene of the Wnt/??- catenin pathway, and we demonstrated a direct cause-effect relationship between Wnt pathway activation and the increased SRp20 expression. Our results also show that SRp20 influences cell proliferation, which suggests it plays a role in the tumorigenicity of CD133+ cells. In conclusion, activation of the Wnt pathway in CD133+ cells and up-regulation of SRp20, which is implicated in tumorigenesis, raises the possibility of a sequential series of molecular events occurring in connection with this process.

// Francesca Puca 1 , Marianna Colamaio 1 , Antonella Federico 1 , Marica Gemei 2 , Nadia Tosti 1 , Andre Uchimura Bastos 1 , Luigi Del Vecchio 2 , Salvatore Pece 3 , Sabrina Battista 1 and Alfredo Fusco 1 1 Istituto di Endocrinologia ed Oncologia Sperimentale - CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Universita degli Studi di Napoli “Federico II”, Naples, Italy 2 CEINGE, Biotecnologie Avanzate, Naples, Italy 3 Istituto Europeo di Oncologia, Milan, Italy Correspondence: Alfredo Fusco, email: // Sabrina Battista, email: // Keywords : HMGA1, cancer stem cells, p53, colon carcinoma, NUMB Received : March 04, 2014 Accepted : April 16, 2014 Published : April 18, 2014 Abstract High-mobility group A1 (HMGA1) proteins are architectural chromatinic proteins, abundantly expressed during embryogenesis and in most cancer tissues, but expressed at low levels or absent in normal adult tissues. Several studies have demonstrated that HMGA1 proteins play a causal role in neoplastic cell transformation. The aim of this study was to investigate the role of these proteins in the control of cancer stem cells (CSCs), which have emerged as a preferred target in cancer therapy, because of their role in cancer recurrence. We observed that HMGA1 is overexpressed in colon tumour stem cell (CTSC) lines compared to normal and colon cancer tissues. We demonstrated that HMGA1 silencing in CTSCs increases stem cell quiescence and reduces self-renewal and sphere-forming efficiency (SFE). The latter, together with the upregulation and asymmetric distribution of NUMB, is indicative of the recovery of an asymmetric division pattern, typical of normal stem cells. We further found that HMGA1 transcriptionally regulates p53, which is known to control the balance between symmetric and asymmetric divisions in CSCs. Therefore, our data indicate a critical role for HMGA1 in regulating both self-renewal and the symmetric/asymmetric division ratio in CSCs, suggesting that blocking HMGA1 function may be an effective anti-cancer therapy.