• Detection of PIK3CA mutations in circulating free DNA in patients with breast cancer.

      Board, Ruth E; Wardley, Andrew M; Dixon, J Michael; Armstrong, Anne C; Howell, Sacha J; Renshaw, Lorna; Donald, Emma; Greystoke, Alastair; Ranson, Malcolm R; Hughes, Andrew; et al. (2010-04)
      Somatic mutations in PIK3CA (encoding a class I phosphoinositide 3 kinase (PI3K) subunit) modulate PI3K signalling to influence tumour behaviour and occur in up to 40% of breast cancers. Inhibitors of PI3K signalling are entering clinical trials, but the impact of PIKC3A mutation on tumour response has yet to be clarified. This study investigated the potential utility of circulating free DNA (cfDNA) as a source for PIK3CA mutation detection in patients with breast cancer. cfDNA extracted (QIAamp Virus spin kit) from blood and matched archival tumour from 46 patients with metastatic breast cancer and 30 patients with localised, operable breast cancer was assessed for hotspot PIK3CA mutations using Amplification Refractory Mutation System (ARMS()) allele-specific PCR and Scorpion probes. PIK3CA mutations were detected in 13/46 (28%) plasma-derived and 10/46 (21%) serum-derived cfDNA samples from metastatic breast cancer patients. In 41 cases with matched tumour and plasma-derived cfDNA data, concordance (same mutation status in plasma and tumour) was 95%. Where a PIK3CA mutation was present in tumour, the 'pick up' in plasma-derived cfDNA was 80%. PIK3CA mutations were present in tumours from 14/30 (47%) localised breast cancers, but no PIK3CA mutations were detected in matched cfDNA. These data demonstrate feasibility and potential utility of cfDNA for PIK3CA mutation detection in patients with metastatic breast cancer. Studies are underway to qualify PIK3CA mutation in cfDNA as a predictive biomarker allowing patient stratification in clinical trials of mechanism-based therapeutics that target PI3K signalling pathways.
    • Erlotinib for frontline treatment of advanced non-small cell lung cancer: a phase II study.

      Giaccone, Giuseppe; Gallegos Ruiz, Marielle; Le Chevalier, Thierry; Thatcher, Nick; Smit, Egbert; Rodriguez, Jose Antonio; Janne, Pasi; Oulid-Aissa, Dalila; Soria, Jean-Charles; Department of Medical Oncology, Vrije Universiteit Medical Center, Amsterdam, the Netherlands. g.giaccone@vumc.nl (2006-10-15)
      PURPOSE: Erlotinib has proven activity in pretreated patients with advanced non-small cell lung cancer (NSCLC). We evaluated erlotinib in the frontline treatment of advanced NSCLC and assessed biological predictors of outcome. EXPERIMENTAL DESIGN: In this phase II study, chemotherapy-naive patients with stage IIIB/IV NSCLC received oral erlotinib (150 mg/d) until disease progression or unacceptable toxicity occurred. Tumor response was assessed every 6 weeks, and samples were analyzed for potential molecular markers of treatment response and survival. The primary end point was the proportion of patients without disease progression after 6 weeks of treatment. RESULTS: Fifty-three patients were eligible. The overall rate of nonprogression at 6 weeks was 52.8% (28 of 53 patients). Tumor response rate was 22.7%, with 1 complete response, 11 partial responses, and 16 cases of stable disease. Responses were seen across most patient clinical characteristics. The median duration of tumor response was 333 days; median overall survival was 391 days; and median time to disease progression was 84 days. Erlotinib was well tolerated, the main treatment-related adverse events being mild-to-moderate rash and diarrhea. Histologic material for biological studies was available in 29 cases. Four of five responders and one patient with stable disease had a classic epidermal growth factor receptor tyrosine kinase mutation. Two progressing patients exhibited epidermal growth factor receptor point mutations (one with T790M mutation), and K-ras mutations were detected in 10 nonresponders. CONCLUSIONS: Erlotinib shows significant antitumor activity in the first-line treatment of advanced NSCLC and may be a viable alternative to chemotherapy. Patient selection cannot easily be based on clinical or biological variables.
    • Expression of hypoxia-inducible factor 1 alpha in thyroid carcinomas.

      Burrows, N; Resch, J; Cowen, R L; Von Wasielewski, R; Hoang-Vu, C; West, Catharine M L; Williams, K J; Brabant, Georg E; School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. (2010-03)
      Hypoxia-inducible factor 1 alpha (HIF-1 alpha) is upregulated by hypoxia and oncogenic signalling in many solid tumours. Its regulation and function in thyroid carcinomas are unknown. We evaluated the regulation of HIF-1 alpha and target gene expression in primary thyroid carcinomas and thyroid carcinoma cell lines (BcPAP, WRO, FTC-133 and 8505c). HIF-1 alpha was not detectable in normal tissue but was expressed in thyroid carcinomas. Dedifferentiated anaplastic tumours (ATCs) exhibited high levels of nuclear HIF-1 alpha staining. The HIF-1 target glucose transporter 1 was expressed to a similar level in all tumour types, whereas carbonic anhydrase-9 was significantly elevated in ATCs. In vitro studies revealed a functionally active HIF-1 alpha pathway in thyroid cells with transcriptional activation observed after graded hypoxia (1% O(2), anoxia) or treatment with a hypoxia mimetic cobalt chloride. High basal and hypoxia-induced expression of HIF-1 alpha in FTC-133 cells that harbour a phosphatase and tensin homologue (PTEN) mutation was reduced by introduction of wild-type PTEN. Similarly, pharmacological inhibition of the phosphoinositide 3-kinase (PI3K) pathway using LY294002 inhibited HIF-1 alpha and HIF-1 alpha targets in all cell lines, including those with B-RAF mutations (BcPAP and 8505c). In contrast, the effects of inhibition of the RAF/MEK/extracellular signal-regulated kinase pathway were restricted by environmental condition and B-RAF mutation status. HIF-1 is functionally expressed in thyroid carcinomas and is regulated not only by hypoxia but also via growth factor signalling pathways and, in particular, the PI3K pathway. Given the strong association of HIF-1 alpha with an aggressive disease phenotype and therapeutic resistance, this pathway may be an attractive target for improved therapy in thyroid carcinomas.
    • Multiplexed assays for detection of mutations in PIK3CA.

      Board, Ruth E; Thelwell, Nicola J; Ravetto, Paul F; Little, Stephen; Ranson, Malcolm R; Dive, Caroline; Hughes, Andrew; Whitcombe, David; Discovery Medicine, AstraZeneca Pharmaceuticals, Macclesfield, UK. ruth.board@astrazeneca.com (2008-04)
      BACKGROUND: Mutations in the PIK3CA gene (phosphoinositide-3-kinase, catalytic, alpha polypeptide) have recently been described in a number of cancers, and their detection is currently limited because of the low sensitivity of conventional sequencing techniques. METHODS: We combined Amplification Refractory Mutation System (ARMS; AstraZeneca) allele-specific PCR and Scorpions (DxS) to develop assays for tumor-borne PIK3CA mutations and used real-time PCR to develop high-throughput multiplexed assays for the most commonly reported PIK3CA mutants (H1047L, H1047R, E542K, E545K). RESULTS: These assays were more sensitive than sequencing and could detect 5 copies of mutant DNA in proportions as low as 0.1% of the total DNA. We assayed DNA extracted from human tumors and detected PIK3CA mutation frequencies of 10.2% in colorectal cancer, 38.7% in breast cancer, 1.9% in lung cancer, and 2.9% in melanoma. In contrast, sequencing detected only 53% of the mutations detected by our assay. CONCLUSIONS: Multiplexed assays, which can easily be applied to clinical samples, have been developed for the detection of PIK3CA mutations.
    • Thyrotropin suppressive therapy in thyroid carcinoma: what are the targets?

      Brabant, Georg E; Department of Endocrinology, Christie Hospital, Wilmslow Road, Manchester M20 4BX, United Kingdom. georg.brabant@manchester.ac.uk (2008-04)