Human epidermal growth factor receptor type 2 protein expression in Chinese metastatic prostate cancer patients correlates with cancer specific survival and increases after exposure to hormonal therapy

Aim： To investigate human epidermal growth factor receptor type 2 （HER2） protein expression and gene amplification in Chinese metastatic prostate cancer patients and their potential value as prognostic factors. Methods： Immunohistochemistry （IHC） was performed to investigate HER2 protein expression in prostate biopsy specimens from 104 Chinese metastatic prostate cancer patients. After 3-11 months of hormonal therapy, 12 patients underwent transurethral resection of the prostate （TURP）. HER2 protein expression of TURP specimens was compared with that of the original biopsy specimens. Of these, 10 biopsy and 4 TURP specimens with HER2 IHC staining scores ≥ 2＋ were investigated for HER2 gene amplification status by fluorescent in situ hybridization （FISH）. Results： Of the 104 prostate biopsy specimens, HER2 protein expression was 0, 1＋, 2＋ and 3＋ in 49 （47.1%）, 45 （43.3%）, 8 （7.7%） and 2 （1.9%） cases, respectively. There was a significant association between HER2 expression and Gleason score （P = 0.026）. HER2 protein expression of prostate cancer tissues increased in 33.3% of patients after hormonal therapy. None of the 14 specimens with HER2 IHC scores 〉 2＋ showed HER2 gene amplification. Patients with HER2 scores 〉 2＋ had a significantly higher chance of dying from prostate cancer than those with HER2 scores of 0 （P = 0.004） and 1＋ （P = 0.034）. Multivariate Cox regression analysis showed that HER2 protein expression intensity was an independent predictor of cancer-related death （P = 0.039）. Conclusion： An HER2 IHC score 〉 2＋ should be defined as HER2 protein overexpression in prostate cancer. Overexpression of HER2 protein in cancer tissue might suggest an increased risk of dying from prostate cancer. HER2 protein expression increases in some individual patients after hormonal therapy.

External validation of the Prostate Cancer Prevention Trial and the European Randomized Study of Screening for Prostate Cancer risk calculators in a Chinese cohort

Several prediction models have been developed to estimate the outcomes of prostate biopsies. Most of these tools were designed for use with Western populations and have not been validated across different ethnic groups. Therefore, we evaluated the predictive value of the Prostate Cancer Prevention Trial （PCPT） and the European Randomized Study of Screening for Prostate Cancer （ERSPC） risk calculators in a Chinese cohort. Clinicopathological information was obtained from 495 Chinese men who had undergone extended prostate biopsies between January 2009 and March 2011. The estimated probabilities of prostate cancer and high-grade disease （Gleason 〉6） were calculated using the PCPT and ERSPC risk calculators. Overall measures, discrimination, calibration and clinical usefulness were assessed for the model evaluation. Of these patients, 28.7% were diagnosed with prostate cancer and 19.4% had high-grade disease. Compared to the PCPT model and the prostate-specific antigen （PSA） threshold of 4 ng m1-1, the ERSPC risk calculator exhibited better discriminative ability for predicting positive biopsies and high-grade disease （the area under the curve was 0.831 and 0.852, respectively, P〈O.01 for both）. Decision curve analysis also suggested the favourable clinical utility of the ERSPC calculator in the validation dataset. Both prediction models demonstrated miscalibration： the risk of prostate cancer and high-grade disease was overestimated by approximately 20% for a wide range of predicted probabilities. In conclusion, the ERSPC risk calculator outperformed both the PCPT model and the PSA threshold of 4 ng ml- z in predicting prostate cancer and high-grade disease in Chinese patients. However, the prediction tools derived from Western men significantly overestimated the probability of prostate cancer and high-grade disease compared to the outcomes of biopsies in a Chinese cohort.

Prostate-specific antigen half-life： a new predictor of progression- free survival and overall survival in Chinese prostate cancer patients

We investigated the potential value of prostate-specific antigen half-life （PSAHL） and decreasing velocity （PSAVd） to predict progression-free survival （PFS） and overall survival （OS） in Chinese patients with prostate cancer. A total of 153 patients treated with hormonal therapy were included in the study. Of these, 78 patients progressed to hormone- refractory prostate cancer （HRPC） and 24 patients died by the end of follow-up. PSAHL was defined as the time during which prostate-specific antigen （PSA） concentration became half of the initial value during the first hormonal therapy. PSAVd reflected the decreasing velocity of PSA during the first hormonal therapy. PFS was defined as the interval from the beginning of hormonal therapy to HRPC. Cox proportional hazards regression analysis was used to evaluate whether PSAHL and PSAVd were significantly associated with PFS and OS. The median PSAHL and PSAVd were 0.50 months and 33.8 ng mL^-1 per month. The median PFS and OS were 22.7 months （95% confidence interval [CI], 22.0-29.6 months） and 43.5 months （95% CI, 37.9-48.4 months）, respectively. On univariate and multivariate analysis, long PSAHL （〉 0.5 months）, metastatic disease, high biopsy Gleason scores （〉 8） and high nadir PSA （〉 0.4 ng mL^-1） were all found to be significantly associated with short PFS. Long PSAHL, high nadir PSA and short PSA doubling time （PSADT 〈 2.0 months） were significantly associated with short OS. There were no significant relationships between PSAVd and either PFS or OS. Thus, PSAHL is a promising new independent predictor of survival. Patients with long PSAHL were identified as those at high risk for a relatively short PFS and OS.

The prognostic factors of effective ketoconazole treatment for metastatic castration-resistant prostate cancer： who can benefit from ketoconazole therapy？

We investigated the prognostic value of some variables of effective ketoconazole treatment for metastatic castration-resistant prostate cancer （mCRPC）. In total, 163 patients with mCRPC were eligible, receiving ketoconazole 200-400 mg three times daily with replacement doses of prednisone. Progression-free survival （PFS） was calculated from the beginning of the ketoconazole therapy to the onset of disease progression. The prognostic value of different variables for PFS was assessed by Cox regression analysis. The median PFS was 2.6 months （0.5-8.6 months） for these patients. The serum testosterone level changed during therapy, which decreased when the prostate-specific antigen （PSA） declined; the serum testosterone level increased as the levels of PSA relapsed. The median PFS values for patients associated with different factors were the following： 1.4 and 3.5 months for a nadir PSA of ≥ 0.2 and 〈0.2 ng ml- 1, respectively （hazard rate （HR）=4.767, P〈0.001）; 3.1 and 1.6 months for a baseline testosterone of ≥0.1 and 〈0.1 ng m1-1, respectively （HR=2.865, P=0.012）; 2.8 and 1.9 months for a baseline haemoglobin of ≥ 120 and 〈120 g 1-1, respectively （HR= 1.605, P〈0.001）; and 3.0 and 1.9 months for a PSA doubling time （PSADT） of ≥ 2.0 and 〈2.0 months, respectively （HR= 1.454, P=-0.017）. A risk model was constructed according to the four factors that divided patients into three subgroups of low risk （0-1 factors）, moderate risk （2 factors） and high risk （3-4 factors） with PFS values of 3.6, 3.0 and 1.4 months, respectively （HR=1.619, P〈0.001）. A nadir PSA of ≥0.2 ng m1-1, a baseline testosterone of 〈0.1 ng m1-1, a baseline haemoglobin of 〈 120 g I- 1 and a PSADT of 〈2 months were associated with a poor PFS. This risk model could provide evidence to predict the survival benefit of ketoconazole therapy.

Chaotic microlasers caused by internal mode interaction for random number generation

Chaotic semiconductor lasers have been widely investigated for generating unpredictable random numbers,especially for lasers with external optical feedback.Nevertheless,chaotic lasers under external feedback are hindered by external feedback loop time,which causes correlation peaks for chaotic output.Here,we demonstrate the first self-chaotic microlaser based on internal mode interaction for a dual-mode microcavity laser,and realize random number generation using the self-chaotic laser output.By adjusting mode frequency interval close to the intrinsic relaxation oscillation frequency,nonlinear dynamics including self-chaos and period-oscillations are predicted and realized numerically and experimentally due to internal mode interaction.The internal mode interaction and corresponding carrier spatial oscillations pave the way of mode engineering for nonlinear dynamics in a solitary laser.Our findings provide a novel and easy method to create controllable and robust optical chaos for high-speed random number generation.