Prevalence of the HOXB13 G84E germline mutation in British men and correlation with prostate cancer risk, tumour characteristics and clinical outcomes.

BACKGROUND: A rare recurrent missense variant in HOXB13 (rs138213197/G84E) was recently reported to be associated with hereditary prostate cancer. Population-based studies have established that, since the frequency of this single-nucleotide polymorphism (SNP) varies between geographic regions, the associated proportion of prostate cancer (PrCa) risk contribution is also highly variable by country. PATIENTS AND METHODS: This is the largest comprehensive case-control study assessing the prevalence of the HOXB13 G84E variant to date and is the first in the UK population. We genotyped 8652 men diagnosed with PrCa within the UK Genetic Prostate Cancer Study (UKGPCS) and 5252 healthy men from the UK ProtecT study. RESULTS: HOXB13 G84E was identified in 0.5% of the healthy controls and 1.5% of the PrCa cases, and it was associated with a 2.93-fold increased risk of PrCa [95% confidence interval (CI) 1.94-4.59; P = 6.27 × 10(-8)]. The risk was even higher among men with family history of PrCa [odds ratio (OR) = 4.53, 95% CI 2.86-7.34; P = 3.1 × 10(-8)] and in young-onset PrCa (diagnosed up to the age of 55 years; OR = 3.11, 95% CI 1.98-5.00; P = 6.1 × 10(-7)). There was no significant association between Gleason Score, presenting prostate specific antigen, tumour-node-metastasis (TNM) stage or NCCN risk group and carrier status. HOXB13 G84E was not associated with overall or cancer-specific survival. We found that the polygenic PrCa risk score (PR score), calculated using the 71 known single-nucleotide polymorphisms (SNPs) associated with PrCa and the HOXB13 G84E variant act multiplicatively on PrCa risk. Based on the estimated prevalence and risk, this rare variant explains ∼1% of the familial risk of PrCa in the UK population. CONCLUSIONS: The clinical importance of HOXB13 G84E in PrCa management has not been established. This variant was found to have no effect on prognostic implications but could be used for stratifying screening, by identifying men at high risk. CLINICAL TRIALS NUMBERS: Prostate Testing for Cancer and Treatment (ProtecT): NCT02044172. UK GENETIC PROSTATE CANCER STUDY: Epidemiology and Molecular Genetics Studies (UKGPCS): NCT01737242.

Pre-clinical and clinical evaluation of PARP inhibitors as tumour-specific radiosensitisers.

Approximately two million fractions of radiotherapy are administered in the UK every year, as part of adjuvant, radical or palliative cancer treatment. For many tumour types, radiotherapy is routinely combined with concomitant chemotherapy as part of adjuvant or radical treatment. In addition, new agents have been developed in recent years and tested in phase 1, 2 and 3 trials concomitantly with radiotherapy or chemoradiotherapy. One such class of drugs, the poly(ADP-ribose) polymerase (PARP) inhibitors, has shown activity in conjunction with radiotherapy in several cancer cell lines. Pre-clinical data suggest that PARP inhibitors may potentiate the effects of radiotherapy in several tumour types, namely lung, colorectal, head and neck, glioma, cervix and prostate cancers. In vitro, PARP inhibitors are radiosensitisers in various cell lines with enhancement ratios of up to 1.7. In vivo, non-toxic doses of PARP inhibitors have been shown to increase radiation-induced growth delay of xenograft tumours in mice. Clinical trials to assess the toxicity and potential benefit of combining radiotherapy with PARP inhibition are now needed.

The impact of carcinoembryonic antigen flare in patients with advanced colorectal cancer receiving first-line chemotherapy.

BACKGROUND: Carcinoembryonic antigen (CEA) flare may have a favourable response to chemotherapy, but its impact on survival is unknown. This study aimed to evaluate the incidence of CEA flare and its impact on objective response rate (ORR), progression-free survival (PFS) and overall survival (OS). PATIENTS AND METHODS: Patients with histologically proven advanced colorectal cancer undergoing first-line chemotherapy with three or more serial CEA measurements (one at baseline and two or more during treatment) were included. Patients were grouped according to CEA kinetic as flare (F), decreasing CEA, normal baseline CEA, stable CEA and increasing CEA (I). RESULTS: From January 2000 to February 2008, 837 patients were screened of whom 670 were eligible. CEA flare occurred in 78 (11.6%) patients. On multivariate analysis, compared with patients with increasing CEA, patients with CEA flare had a significantly better ORR [I versus F: 11% versus 73%; risk ratio (RR): 27.96; 95% confidence interval (CI): 9.55-81.88; P < 0.001], PFS (median 3.1 versus 8.3 months; RR: 0.38; 95% CI: 0.26-0.56; P < 0.001) and OS (median 10.9 versus 17.7 months; RR: 0.53; 95% CI: 0.34-0.82; P < 0.001). CONCLUSIONS: Compared with patients with rising CEA, flare was an independent favourable predictive and prognostic factor for tumour response and survival.