Recommended testing algorithms for NTRK gene fusions in pediatric and selected adult cancers: Consensus of a Singapore Task Force.

The occurrence of neurotrophic tyrosine receptor kinase (NTRK) gene fusions in a wide range of tumor types presents an attractive opportunity for using a tropomyosin receptor kinase (TRK) inhibitor as cancer therapy. Recent clinical studies have demonstrated highly efficacious outcomes associated with the use of TRK inhibitors, such as larotrectinib and entrectinib in NTRK fusion-bearing cancers, in both adult and pediatric populations. While NTRK gene fusions are commonly found in some uncommon adult and pediatric malignancies, they are also found, albeit rarely, in a wide range of more common malignancies. The potential value of testing for NTRK gene fusions in practically all advanced malignancies is underpinned by the remarkable therapeutic outcomes that TRK inhibitors offer. This requirement presents practical and financial challenges in real-world oncological practice. Furthermore, different testing platforms exist to detect NTRK gene fusions, each with its advantages and disadvantages. It is, therefore, imperative to develop strategies for NTRK gene fusion testing in an attempt to optimize the use of limited tissue specimen and financial resources, and to minimize the turnaround time. A multidisciplinary task force of Singapore medical experts in both public and private sectors was convened in late 2020 to propose testing algorithms for adult colorectal tumors, sarcomas, non-small cell lung cancer, and pediatric cancers, with particular adaptation to the Singapore oncological practice. The recommendations presented here highlight the heterogeneity of NTRK-fusion positive cancers, and emphasize the need to customize the testing methods to each tumor type to optimize the workflow.

Clinical genetic testing outcome with multi-gene panel in Asian patients with multiple primary cancers.

BACKGROUND: Developing multiple cancers is an indicator of underlying hereditary cancer predisposition, but there is a paucity of data regarding the clinical genetic testing outcomes of these patients. METHODS: We compared cancer index patients with ≥2 primary malignancies versus 1 primary cancer who underwent clinical evaluation and testing with multi-gene panels comprising up to 49 genes from 1998-2016. RESULTS: Among 1191 cancer index patients, 80.6%, 17.2%, and 2.2% respectively had 1, 2, and ≥3 primary malignancies. For patients with 2 primary cancers (n=205), the most common cancer pairs were bilateral breast (37.5%), breast-ovary (11.7%), endometrium-ovary (9.2%), colon-endometrium (3.9%) and colon-colon (3.4%). 42.3% patients underwent gene testing including 110/231 (47.6%) with multiple malignancies. Pathogenic variants were found more frequently in younger patients, in those with a family history of cancer related to the suspected syndrome, and a trend towards significance in those with multiple primary cancers (35.5% vs. 25.6%, p = 0.09). In patients with multiple cancers, pathogenic variants were most commonly identified in BRCA1 (38.5%), BRCA2 (17.9%), and the mismatch repair genes (20.5%), while 23.1% of pathogenic mutations were in other moderate- to high-penetrance cancer predisposition genes including APC, ATM, MUTYH, PALB2, RAD50 and TP53. CONCLUSION: Patients with multiple cancers were more likely to carry pathogenic mutations than those with single cancer. About three-quarters of deleterious mutations in patients with multiple primary cancers were in BRCA1/2 and the mismatch repair genes, but multi-gene panel testing facilitated the detection of mutations in another 6 genes and is warranted in this high-risk population.

Tumour genetics and genomics to personalise cancer treatment.

Personalising cancer treatment to optimise therapeutic efficacy while minimising exposure to the toxicities of ineffective drugs is the holy grail of medical oncology. Clinical parameters and conventional histopathological characterisations of cancers are no longer adequate to guide the practising oncologists in treatment planning. The explosion of knowledge in cancer molecular biology has led to the availability of tumour-specific molecules that serve as predictive and prognostic markers. In breast cancer, HER-2 positivity is a good predictor for success of anti-HER-2 trastuzumab monoclonal antibody therapy. K-ras mutational status predicts the likelihood of response to anti-EGFR monoclonal antibodies in advanced colorectal cancers. Similarly, EGFR mutational status in pulmonary adenocarcinoma is highly predictive for responses or otherwise to tyrosine kinase inhibitors. Notwithstanding our deeper understanding of tumour biology and the availability of predictive and prognostic laboratory tools, we are still far from achieving our dream of the perfect personalised cancer treatment, as each tumour in a particular patient is unique to itself. A much coveted, real-time, anti-tumour drug sensitivity testing in the future may one day pave the way for truly treating the right tumour with the right drug in the right patient.

Multi-centre phase II trial of Thalidomide in the treatment of unresectable hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a hypervascular tumour, which overexpresses vascular endothelial growth factor. Thalidomide is an antiangiogenic agent with activity in refractory multiple myeloma. The purpose of this multi-centre phase II study was to evaluate the efficacy and toxicity of thalidomide in patients with advanced HCC. From February 2000 to November 2001, 37 patients with histologically proven, bi-dimensionally measurable advanced, unresectable HCC were enrolled. The starting dose of Thalidomide was 100 mg per day and escalated weekly by 100 mg to a maximum dose of 800 mg/day according to individual patient tolerance. Radiological tumour response and treatment related toxicities were prospectively assessed. Thirty-seven patients were evaluable for toxicity and 24 patients were evaluable for response. The median Thalidomide dose was 400 mg/day. There was no complete response (CR). One patient had a radiological partial response (PR) (3%; 95% confidence interval [95% CI], 0% to 8%) and six (16%) patients had stable disease for more than 6 months. Somnolence and fatigue were the most common side effects, occurring in 84% and 73% of patients respectively. Thalidomide monotherapy is tolerable and associated with modest antitumour activity in advanced HCC.

Combined endostatin/sFlt-1 antiangiogenic gene therapy is highly effective in a rat model of HCC.

Hepatocellular carcinoma (HCC) is regarded as a suitable target for antiangiogenic strategies. However, antiangiogenic agents aimed at single targets can be neutralized by upregulation of other proangiogenic factors. Therefore, combined approaches addressing at least two angiogenic targets should be more effective. Employing an appropriate rat hepatoma model, we examined the effects of sFlt-1 (soluble vascular endothelial growth factor [VEGF] receptor 1 as an indirect inhibitor of angiogenesis) and endostatin (a direct inhibitor of angiogenesis) in both single-agent as well as combined approaches under in vitro and in vivo conditions. Similar to human HCC, rat Morris hepatoma (MH) cells secreted high levels of VEGF, but no endogenous sFlt-1. Parental MH or MHES(r) cells, stably expressing rat endostatin, were adenovirally transduced either with AdsFlt-1 (encoding sFlt-1) or control vector Adnull (containing no transgene), followed by subcutaneous inoculation into syngeneic ACI rats. Compared with MH/Adnull cells, expressing no antiangiogenic factors at all, tumor weights were reduced fourfold in the MHES(r)/Adnull group, 19-fold in the MH/AdsFlt-1-group, and 77-fold in the MHES(r)/AdsFlt-1 combination therapy group. Analysis of variance did not show a significant interaction between the effects of the two factors ES(r) and sFlt-1; their effects multiplied. In conclusion, combined expression of sFlt-1 and endostatin effectively suppresses HCC growth under in vivo conditions. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).