Emerging roles for PIWI proteins in cancer

It is generally accepted that PIWI proteins are predominately expressed in the germline but absent in somatic tissues. Their best-characterized role is to suppress transposon expression, which ensures genomic stability in the germline. However, increasing evidence has suggested that PIWI proteins are linked to the hallmarks of cancer defined by Weinberg and Hanahan, such as cell proliferation, anti-apoptosis, genomic instability, invasion and metastasis. This provides new possibilities for anticancer therapies through the targeting of PIWI proteins, which may have fewer side effects due to their potential classification as a CTA (cancer/testis antigen). Furthermore, PIWI has been proposed to act as a diagnostic and prognostic marker for many types of cancer, and even to differentiate early- and late-stage cancers. We herein summarize the latest progress in this exciting field, hoping to encourage new investigations of PIWIs in cancer biology that will help to develop new therapeutics for clinical application.

Cost-effectiveness analysis of prognostic gene expression signature-based stratification of early breast cancer patients

BACKGROUND

The individual risk of recurrence in hormone receptor-positive primary breast cancer patients determines whether adjuvant endocrine therapy should be combined with chemotherapy. Clinicopathological parameters and molecular tests such as EndoPredict(®) (EPclin) can support decision making in patients with estrogen receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative cancer.

OBJECTIVE

Using a life-long Markov state transition model, we determined the health economic impact and incremental cost effectiveness of EPclin-based risk stratification in combination with clinical guidelines [German-S3, National Comprehensive Cancer Center Network (NCCN), and St. Gallen] to decide on chemotherapy use.

METHODS

Information on overall and metastasis-free survival came from Austrian Breast & Colorectal Cancer Study Group clinical trials 6/8 (n = 1,619) and published literature. Effectiveness was assessed as quality-adjusted life-years (QALYs). Costs (2010) were assessed from a German third-party payer perspective.

RESULTS

Lifetime costs per patient ranged from <euro>28,268 (St.Gallen and EPclin) to <euro>33,756 (NCCN). Due to an imperfect prognostic value and differences in chemotherapy use, strategies achieved between 13.165 QALYs (NCCN) and 13.173 QALYs (EPclin alone) per patient. Using German-S3 as reference, three strategies showed dominant results (St. Gallen and EPclin, German-S3 and EPclin, EPclin alone). Compared to German-S3, the addition of EPclin saved <euro>3,388 and gained 0.002 QALYs per patient. Combining guidelines with EPclin remained preferable in sensitivity analysis.

CONCLUSION

Our study suggests that molecular markers can be sensibly combined with clinical guidelines to determine the risk profile of adjuvant breast cancer patients. Compared with the current German best practice (German-S3), combinations of EPclin with the St. Gallen, German-S3 or NCCN guideline and EPclin alone were dominant from the perspective of the German healthcare system.

Managing the future: the Special Virus Leukemia Program and the acceleration of biomedical research

After the end of the Second World War, cancer virus research experienced a remarkable revival, culminating in the creation in 1964 of the United States National Cancer Institute's Special Virus Leukemia Program (SVLP), an ambitious program of directed biomedical research to accelerate the development of a leukemia vaccine. Studies of cancer viruses soon became the second most highly funded area of research at the Institute, and by far the most generously funded area of biological research. Remarkably, this vast infrastructure for cancer vaccine production came into being before a human leukemia virus was shown to exist. The origins of the SVLP were rooted in as much as shifts in American society as laboratory science. The revival of cancer virus studies was a function of the success advocates and administrators achieved in associating cancer viruses with campaigns against childhood diseases such as polio and leukemia. To address the urgency borne of this new association, the SVLP's architects sought to lessen the power of peer review in favor of centralized Cold War management methods, fashioning viruses as "administrative objects" in order to accelerate the tempo of biomedical research and discovery.

Novel rolling circle amplification and DNA origami-based DNA belt-involved signal amplification assay for highly sensitive detection of prostate-specific antigen (PSA)

Prostate-specific antigen (PSA) is one of the most important biomarkers for the early diagnosis and prognosis of prostate cancer. Although many efforts have been made to achieve significant progress for the detection of PSA, challenges including relative low sensitivity, complicated operation, sophisticated instruments, and high cost remain unsolved. Here, we have developed a strategy combining rolling circle amplification (RCA)-based DNA belts and magnetic bead-based enzyme-linked immunosorbent assay (ELISA) for the highly sensitive and specific detection of PSA. At first, a 96-base circular DNA template was designed and prepared for the following RCA. Single stranded DNA (ssDNA) products from RCA were used as scaffold strand for DNA origami, which was hybridized with three staple strands of DNA. The resulting DNA belts were conjugated with multiple enzymes for signal amplification and then employed to magnetic bead based ELISA for PSA detection. Through our strategy, as low as 50 aM of PSA can be detected with excellent specificity.

Assessing progress in reducing the burden of cancer mortality, 1985-2005

PURPOSE

Measuring the effect of cancer interventions must take into account rising cancer incidence now that people live longer because of declines in mortality from cardiovascular disease (CVD). Cancer mortality rates in the population do not accomplish this objective. We sought a measure that would reveal the effects of changing mortality rates from other diseases.

METHODS

We obtained annual breast, colorectal, lung, and prostate cancer mortality rates from the Surveillance, Epidemiology, and End Results registries; we obtained noncancer mortality rates from national death certificates, 1975 to 2005. We used life-table methods to calculate the burden of cancer mortality as the average person-years of life lost (PYLL) as a result of cancer (cancer-specific PYLL) and quantify individual-and perhaps offsetting-contributions of the two factors that affect cancer-specific PYLL: mortality rates as a result of cancer and other-cause mortality.

RESULTS

Falling cancer mortality rates reduced the burden of mortality from leading cancers, but increasing cancer incidence as a result of decreasing other-cause mortality rates partially offset this progress. Between 1985 and 1989 and between 2000 and 2004, the burden of lung cancer in males declined by 0.1 year of life lost. This decline reflects the sum of two effects: decreasing lung cancer mortality rates that reduced the average burden of lung cancer mortality by 0.33 years of life lost and declining other-cause mortality rates that raised it by 0.23 years. Other common cancers showed similar patterns.

CONCLUSION

By using a measure that accounts for increased cancer incidence as a result of improvements in CVD mortality, we find that prior assessments have underestimated the impact of cancer interventions.

Perspective: Flicking with flow: Can microfluidics revolutionize the cancer research?

According to the World Health Organization, cancer is one of the leading causes of death worldwide. Cancer research, in its all facets, is truly interdisciplinary in nature, cutting across the fields of fundamental and applied sciences, as well as biomedical engineering. In recent years, microfluidics has been applied successfully in cancer research. There remain, however, many elusive features of this disease, where microfluidic systems could throw new lights. In addition, some inherent features of microfluidic systems remain unexploited in cancer research. In this article, we first briefly review the advancement of microfluidics in cancer biology. We then describe the biophysical aspects of cancer and outline how microfluidic system could be useful in developing a deeper understanding on the underlying mechanisms. We next illustrate the effects of the confined environment of microchannel on cellular dynamics and argue that the tissue microconfinement could be a crucial facet in tumor development. Lastly, we attempt to highlight some of the most important problems in cancer biology, to inspire next level of microfluidic applications in cancer research.

Selecting breast cancer patients for chemotherapy: the opening of the UK OPTIMA trial

The mortality from breast cancer has improved steadily over the past two decades, in part because of the increased use of more effective adjuvant therapies. Thousands of women are routinely treated with intensive chemotherapy, which can be unpleasant, is expensive and is occasionally hazardous. Oncologists have long known that some of these women may not need treatment, either because they have a low risk of relapse or because they have tumour biology that makes them less sensitive to chemotherapy and more suitable for early adjuvant endocrine therapy. There is an urgent need to improve patient selection so that chemotherapy is restricted to those patients who will benefit from it. Here we review the emerging technologies that are available for improving patient selection for chemotherapy. We describe the OPTIMA trial, which has just opened to recruitment in the UK, is the latest addition to trials in this area, and is the first to focus on the relative cost-effectiveness of alternate predictive assays.