PhD candidate, Queensland Univeristy of Technology/Institute of Health and Biomedical Innovation
A simple blood test to serve as a liquid biopsy
My PhD research over the past 3.5 years has been focussed on the development of non-invasive diagnostic tools for the early detection of metastatic cancers. Metastasis remains the major cause of cancer related deaths and very little is understood about the metastatic seeds in circulation, commonly termed circulating tumour cells (CTCs). My research, through the use of state of the art CTC isolation methodologies has led to a number of significant advances in knowledge in the areas of head and neck cancers (HNCs). My work has clarified the need to move away from epitope dependent platforms to more unbiased CTC capture methodologies which are able to capture single and CTC clusters. My work in CTC clusters has been one of the few early studies documenting these in head and neck cancer patients and have been reported to have a higher metastatic potential than single CTCs. The bottleneck in the field has been to expand these rare cancer cells from the patient’s blood. More recently, I was able to report, for the first time in HNCs, short term CTC expansion outside the patient’s body using novel culture formulations, growth formats (2D/3D) under hypoxic conditions. These short term cultures can be used for the testing of medicines and drug sensitivity assays to determine whether culture responses parallel patient responses to therapy. My research has also revealed that biomarkers are expressed on CTCs which can be used to select patients for immunotherapy – a current unmet clinical need. My research from my PhD has led to 12 publications consisting of 6 research articles (all first author), 3 reviews (all first author), 3 book chapters (2 first author, 1 second author) with the majority in reputable Q1 cancer journals.
Abstract: Minimally invasive techniques are required for the identification of head and neck cancer (HNC) patients who are at an increased risk of metastasis, or are not responding to therapy. An approach utilised in other solid cancers is the identification and enumeration of circulating tumour cells (CTCs) in the peripheral blood of patients. Low numbers of CTCs has been a limiting factor in the HNC field to date. Here we present a methodology to expand HNC patient derived CTCs ex-vivo. As a proof of principle study, 25 advanced stage HNC patient bloods were enriched for circulating tumour cells through negative selection and cultured in 2D and 3D culture environments under hypoxic conditions (2% O2, 5% CO2). CTCs were detected in 14/25 (56%) of patients (ranging from 1-15 CTCs/5 mL blood). Short term CTC cultures were successfully generated in 7/25 advanced stage HNC patients (5/7 of these cultures were from HPV+ patients). Blood samples from which CTC culture was successful had higher CTC counts (p = 0.0002), and were predominantly from HPV+ patients (p = 0.007). This is, to our knowledge, the first pilot study to culture HNC CTCs ex-vivo. Further studies are warranted to determine the use of short term expansion in HNC and the role of HPV in promoting culture success.
Pub.: 16 Aug '16, Pinned: 24 Aug '17
Abstract: Whilst locoregional control of head and neck cancers (HNCs) has improved over the last four decades, long-term survival has remained largely unchanged. A possible reason for this is that the rate of distant metastasis has not changed. Such disseminated disease is reflected in measurable levels of cancer cells in the blood of HNC patients, referred to as circulating tumour cells (CTCs). Numerous marker-independent techniques have been developed for CTC isolation and detection. Recently, microfluidics-based platforms have come to the fore to avoid molecular bias. In this pilot, proof of concept study, we evaluated the use of the spiral microfluidic chip for CTC enrichment and subsequent detection in HNC patients. CTCs were detected in 13/24 (54%) HNC patients, representing both early to late stages of disease. Importantly, in 7/13 CTC-positive patients, CTC clusters were observed. This is the first study to use spiral microfluidics technology for CTC enrichment in HNC.
Pub.: 16 Feb '17, Pinned: 24 Aug '17
Abstract: Blockade of the PD-1/PD-L1 immune checkpoint pathway is emerging as a promising immunotherapeutic approach for the management and treatment of head and neck cancer patients who do not respond to 1st/2nd line therapy. However, as checkpoint inhibitors are cost intensive, identifying patients who would most likely benefit from anti PD-L1 therapy is required. Developing a non-invasive technique would be of major benefit to the patient and to the health care system.We report the case of a 56 year old man affected by a supraglottic squamous cell carcinoma (SCC). A CT scan showed a 20 mm right jugulodigastric node and suspicious lung lesions. The lung lesion was biopsied and confirmed to be consistent with SCC. The patient was offered palliative chemotherapy. At the time of presentation, a blood sample was taken for circulating tumour cell (CTC) analysis. The dissemination of cancer was confirmed by the detection of CTCs in the peripheral blood of the patient, measured by the CellSearch System (Janssen Diagnostics). Using marker-independent, low-shear spiral microfluidic technology combined with immunocytochemistry, CTC clusters were found in this patient at the same time point, expressing PD-L1.This report highlights the potential use of CTCs to identify patients which might respond to anti PD-L1 therapy.
Pub.: 18 May '17, Pinned: 24 Aug '17