James P. Stewart

Correlation of TACC3, FGFR3, MMSET and p21 expression with the t(4;14)(p16.3;q32) in multiple myeloma.

The t(4;14)(p16;q32) translocation seen in c. 18% of newly diagnosed multiple myeloma (MM) cases, results in FGFR3 activation and creation of an IGH/MMSET fusion transcript. We have recently shown that FGFR3 is activated in only 75% of t(4;14)+ cases, suggesting that alternative genes near the breakpoint may be involved in the transforming event. The gene, TACC3, located just 50 kb telomeric of FGFR3, with transforming capacity, therefore represented a candidate gene. Using a real‐time quantitative polymerase chain reaction‐based approach on a cohort of 54 patients, we found a statistically significant, twofold increase in TACC3 expression in t(4;14)+ cases. TACC3, MMSET and p21 values were positively correlated in all cases and, of particular interest, six patient samples [three t(4;14)−, three t(4;14)+] samples showed a joint up‐regulation of TACC3, MMSET and p21. Although a poor prognosis is linked with elevated MMSET expression, an extended follow‐up period will be required to evaluate the significance of elevated TACC3 and p21 expression in this subgroup of MM.

Role of osteoblast suppression in multiple myeloma.

Multiple myeloma is the most common form of plasma cell dyscrasia and virtually all cases of myeloma exhibit osteolytic lesions, which result in bone pain, pathological fractures, spinal cord compression, and hypercalcaemia. Malignant plasma cells disrupt the delicate balance between bone formation and bone resorption, which ultimately leads to the debilitating osteolytic lesions. This review focuses principally on mechanisms of osteoblast inhibition by malignant plasma cells with emphasis placed on our experimental findings, which support a model for abnormal Wnt signaling in osteoblast suppression. We describe how excessive amounts of soluble Wnt inhibitors secreted by malignant plasma cells in multiple myeloma could promote osteolytic lesions, tumor growth, suppress hematopoiesis, prevent proper engraftment, and expansion of transplanted stem cells. Finally, we detail current therapies shown to disrupt the interaction between the myeloma cell and the microenvironment, leading to activation of osteoblasts. J. Cell. Biochem. 98: 1–13, 2006.

CYR61/CCN1 overexpression in the myeloma microenvironment is associated with superior survival and reduced bone disease

Secreted protein CCN1, encoded by CYR61, is involved in wound healing, angiogenesis, and osteoblast differentiation. We identified CCN1 as a microenvironmental factor produced by mesenchymal cells and overexpressed in bones of a subset of patients with monoclonal gammopathy of undetermined significance (MGUS), asymptomatic myeloma (AMM), and multiple myeloma (MM). Our analysis showed that overexpression of CYR61 was independently associated with superior overall survival of MM patients enrolled in our Total Therapy 3 protocol. Moreover, elevated CCN1 was associated with a longer time for MGUS/AMM to progress to overt MM. During remission from MM, high levels of CCN1 were associated with superior progression-free and overall survival and stratified patients with molecularly defined high-risk MM. Recombinant CCN1 directly inhibited in vitro growth of MM cells, and overexpression of CYR61 in MM cells reduced tumor growth and prevented bone destruction in vivo in severe combined immunodeficiency-hu mice. Signaling through αvβ3 was required for CCN1 prevention of bone disease. CYR61 expression may signify early perturbation of the microenvironment before conversion to overt MM and may be a compensatory mechanism to control MM progression. Therapeutics that upregulate CYR61 should be investigated for treating MM bone disease.

Standardising RNA profiling based biomarker application in cancer - the need for robust control of technical variables

Histopathology-based staging of colorectal cancer (CRC) has utility in assessing the prognosis of patient subtypes, but as yet cannot accurately predict individual patients treatment response. Transcriptomics approaches, using array based or next generation sequencing (NGS) platforms, of formalin fixed paraffin embedded tissue can be harnessed to develop multi-gene biomarkers for predicting both prognosis and treatment response, leading to stratification of treatment. While transcriptomics can shape future biomarker development, currently <1% of published biomarkers become clinically validated tests, often due to poor study design or lack of independent validation. In this review of a large number of CRC transcriptional studies, we identify recurrent sources of technical variability that encompass collection, preservation and storage of malignant tissue, nucleic acid extraction, methods to quantitate RNA transcripts and data analysis pipelines. We propose a series of defined steps for removal of these confounding issues, to ultimately aid in the development of more robust clinical biomarkers.

Prospective patient stratification into robust cancer-cell intrinsic subtypes from colorectal cancer biopsies

Colorectal cancer (CRC) biopsies underpin accurate diagnosis, but are also relevant for patient stratification in molecularly‐guided clinical trials. The consensus molecular subtypes (CMSs) and colorectal cancer intrinsic subtypes (CRISs) transcriptional signatures have potential clinical utility for improving prognostic/predictive patient assignment. However, their ability to provide robust classification, particularly in pretreatment biopsies from multiple regions or at different time points, remains untested. In this study, we undertook a comprehensive assessment of the robustness of CRC transcriptional signatures, including CRIS and CMS, using a range of tumour sampling methodologies currently employed in clinical and translational research. These include analyses using (i) laser‐capture microdissected CRC tissue, (ii) eight publically available rectal cancer biopsy data sets (n = 543), (iii) serial biopsies (from AXEBeam trial, NCT00828672; n = 10), (iv) multi‐regional biopsies from colon tumours (n = 29 biopsies, n = 7 tumours), and (v) pretreatment biopsies from the phase II rectal cancer trial COPERNCIUS (NCT01263171; n = 44). Compared to previous results obtained using CRC resection material, we demonstrate that CMS classification in biopsy tissue is significantly less capable of reliably classifying patient subtype (43% unknown in biopsy versus 13% unknown in resections, p = 0.0001). In contrast, there was no significant difference in classification rate between biopsies and resections when using the CRIS classifier. Additionally, we demonstrated that CRIS provides significantly better spatially‐ and temporally‐ robust classification of molecular subtypes in CRC primary tumour tissue compared to CMS (p = 0.003 and p = 0.02, respectively). These findings have potential to inform ongoing biopsy‐based patient stratification in CRC, enabling robust and stable assignment of patients into clinically‐informative arms of prospective multi‐arm, multi‐stage clinical trials.