What the scientists are saying…

The first pig-human embryos A viable part-human, part-pig embryo has been created for the first time. According to a report in the journal Cell, researchers in the US injected human stem cells – the type capable of growing into almost any form of tissue – into more than 2,000 early pig embryos, then implanted them into surrogate sows. Around 185 of these hybrids continued to grow, until they were removed at 28 days – and crucially, the tiny proportion of human cells in them seemed to be functioning (about one in 10,000 of the cells were human, making the chimeras 0.01% human). Though such research raises many ethical concerns, the idea is that, eventually, scientists will be able to grow human organs in animals, to provide a ready supply for transplants.

Prostate scans improve diagnosis Survival rates for prostate cancer would improve if all men suspected of having the disease were given MRI scans, a new study suggests. Currently, men with clinical signs of cancer (such as raised PSA levels) are usually given a biopsy: more than 100,000 a year are carried out in the UK. But as a diagnostic test, this exploratory surgery is far from ideal. Biopsies can have painful, and sometimes serious side effects. Being based on samples taken from various parts of the prostate, they’re also not very accurate: biopsies can miss the cancer altogether, and do not reliably distinguish between aggressive forms of the disease that require immediate treatment and those that require only monitoring. To test whether using advanced MP-MRI scans would be more effective, a team from University College London arranged for 576 men with signs of prostate cancer to be given both scans and biopsies. Their results suggest that if all patients were given an initial MRI, one in four could safely be spared having an immediate biopsy; that using the scans could reduce rates of overdiagnosis – when patients are given treatments for cancers that later prove harmless – by 5%; and that carrying out biopsies guided by scan findings could lead to up to 18% more cases of clinically significant cancers being detected. “This is the biggest leap forward in prostate cancer diagnosis in decades, with the potential to save many lives,” said Angela Culhane, chief executive of Prostate Cancer UK.

Distress linked to cancer risk People who suffer from anxiety or depression have an increased risk of dying from several forms of cancer, new research has suggested. The meta-analysis of 16 cohort studies looked at how the total 163,363 participants had rated their levels of mental distress at one point in time, and then followed up what happened to them over the next ten years – including whether they’d died of cancer. The researchers found that people who had reported having the highest levels of distress were 32% more likely to have died from one of five types of cancer (including pancreatic cancer, and leukaemia) than those with the lowest levels. There is growing evidence that psychological stress has an impact on physical health. However, the findings do not mean that unhappiness causes cancer: it could be that people in mental distress eat unhealthily – and poor diet is linked to cancer; or that they don’t attend cancer screenings, leading to delayed diagnoses; or that they fail to follow up their treatment. It could also be that people feel depressed because their general health is poor, which could, in turn, reduce their chances of surviving cancer.

Sex painful for many women A sizeable minority of women experience pain during sex, according to a new study. The findings come from the National Survey of Sexual Attitudes and Lifestyle, which included 8,869 British women aged 16 to 74 interviewed between 2010 and 2012. Among the 6,669 who had been sexually active over the past year, 7.5% reported having painful sex (dyspareunia) for at least three months; a quarter of this group reported “morbid” pain – symptoms occurring always or very often for at least six months, and leaving them feeling distressed. The most likely to be affected were women aged 55 to 64 (10.4%), and 16 to 24 (9.5%). Among the women who weren’t sexually active, 2.05% said they avoided sex because it was painful, or they feared it would be. The study didn’t draw conclusions about the causes of painful sex but it did find that it was associated with reports of vaginal dryness and anxiety.