Why colorectal cancer death rate is rising in people under-55

*Drug hope for acute myeloid leukaemia as spider peptides battle superbugs, tumour

A new report finds that colorectal cancer mortality rates have increased in adults under 55 since the mid-2000s after falling for decades, strengthening evidence that previously reported increases in incidence in this age group are not solely the result of more screening. The rise was confined to white individuals according to the report, which appears in the Journal of the American Medical Association.

As reported previously by American Cancer Society investigators, colorectal cancer (CRC) incidence has been increasing in the United States among adults younger than 55 years since at least the mid-1990s. The increase thus far is confined to white men and women and is most rapid for metastatic disease. CRC mortality overall is declining rapidly, masking trends in young adults, which have not been comprehensively examined.

For the current study, ACS investigators led by Rebecca Siegel, MPH analyzed CRC mortality among persons aged 20 to 54 years by race from 1970 through 2014 using data from the National Center for Health Statistics. The analysis included 242,637 people ages 20 to 54 who died from CRC between 1970 and 2014.

CRC mortality rates among those ages 20 to 54 declined from 6.3 per 100,000 in 1970 to 3.9 in 2004, at which point mortality rates began to increase by 1.0 per cent annually, eventually reaching 4.3 per 100,000 in 2014. The increase was confined to white individuals, among whom mortality rates increased by 1.4 per cent per year, from 3.6 in 2004 to 4.1 in 2014. Among black individuals, mortality declined throughout the study period at a rate of 0.4 per cent to 1.1 per cent annually (from 8.1 in 1970 to 6.1 in 2014). Among other races combined, mortality rates declined from 1970-2006 and were stable thereafter.

While mortality remained stable in white individuals ages 20 to 29 from 1988-2014, it increased from 1995-2014 by 1.6 per cent per year in those ages 30 to 39 years, and from 2005-2014 by 1.9 per cent per year for those ages 40 to 49 years and by 0.9 per cent per year for those ages 50 to 54 years. Conversely, rates declined in black individuals in every age group.

The authors note that these disparate racial patterns are inconsistent with trends in major risk factors for colorectal cancer like obesity, which is universally increasing.

The authors say rising colorectal cancer mortality in people in their 50s was particularly unexpected because screening, which can prevent cancer as well as detect it early, when it is more curable, has been recommended starting at age 50 for decades.

Screening prevalence has increased for all age groups over 50, but is lower in people 50 to 54 than in those 55 and older: 44 per cent versus 62 per cent, respectively, in 2013, according to the National Health Interview Survey.

Drug hope for acute myeloid leukaemia
Also, a new drug that strips cancer cells of their “immortality” could help to treat patients suffering from one of the most aggressive forms of leukaemia. The drug candidate, called HXR9, works by preventing the cancer cells from sidestepping the natural process that causes unhealthy and damaged cells to die, known as apoptosis.

Researchers at the University of Bradford have found the drug could be used to treat acute myeloid leukaemia (AML), which is responsible for 2,500 deaths in the United Kingdom (UK) and 265,000 worldwide each year.

The drug targets a particular family of genes, called HOX genes, which are involved in controlling the rapid growth of cells. In adults these are switched off but in cancer cells they can be turned back on. This helps to give the cancer cells the ability to continuously grow and divide by circumventing the normal mechanisms that trigger apoptosis – effectively making them immortal.

Prof. Richard Morgan, Director of the Institute for Cancer Therapeutics at the University of Bradford who led the research, said HXR9 strips the cancer cells of this ability by turning off the HOX genes.

In the latest study, which is published in the journal Oncotarget, the researchers wanted to see if the same drug could be used to treat difficult to treat blood cancers.

Also, as antibiotic resistance rises and fears over superbugs grow, scientists are looking for new treatment options. One area of focus is antimicrobial peptides (AMPs), which could someday be an alternative to currently prescribed antibiotics, many of which are becoming increasingly useless against some bacteria. Now, a team reports in ACS Chemical Biology that they have improved the antimicrobial – and anticancer – properties of an AMP from a spider.

Researchers are trying to find alternatives to traditional antibiotics, and one such possibility is a group of peptides called AMPs. These peptides are found in all plants and animals as a type of immune response and have been shown to be potent antibiotics in the laboratory. Gomesin, an AMP from the Brazilian spider Acanthoscurria gomesiana can function as an antibiotic, but it also has anticancer activity. When gomesin was synthesized as a circle instead of as a linear structure, these characteristics were enhanced. Sónia Troeira Henriques and colleagues wanted to further boost the peptide’s traits.

The team made several variations of the cyclic gomesin peptide and found that some of these were 10 times better at killing most bacteria than the previously reported cyclic form. In other experiments, the new AMPs specifically killed melanoma and leukemia cells, but not breast, gastric, cervical or epithelial cancer cells. The researchers determined that the modified peptides killed bacteria and cancer cells in a similar way – by disrupting the cells’ membranes. The group also notes that the modified AMPs were non-toxic to healthy blood cells.