Worldwide cancer accounts for about 10 million deaths each year, with 3 million in China. Many important causes of common cancers are known, but the evidence is mainly from studies of Western populations. There is still a large evidence gap in China where the cancer rates, risk exposures, and genetic susceptibilities differ from those in Western populations. Uncertainty also persists about causal relevance of certain risk factors (e.g. obesity) for specific cancers and cancer subtypes (such as oesophageal squamous cell carcinoma), and about the complex interplay of host susceptibility, lifestyle, and chronic infection in cancer aetiology.
Our previous research in CKB has demonstrated expected and unexpected findings about the relevance of many conventional risk factors (e.g. tobacco smoking, H pylori) for major cancers in Chinese adults. We will extend our work to less common cancers and cancer subtypes and study the relevance of emerging risk factors and biological mechanisms linking selected exposures with specific cancers.
Our current and planned work aims:
- to quantify the associations of certain conventional risk factors (e.g. alcohol, diet, obesity, and reproductive factors) with risks of site-specific cancers and, where applicable, to clarify the causality of the associations;
- to examine the associations of certain risk factors (e.g. metabolic factors) with risks of specific cancer subtypes across different organ systems based on histology (e.g. adenocarcinoma);
- to assess the causal relevance of chronic pathogen infections, both independently and jointly, in the aetiology of specific cancers, and to explore the role of host immunity (e.g. HLA) in modifying the risks;
- to improve existing, and develop new, risk prediction models for specific cancers using extensive lifestyle, infectious marker and genetic data;
- to explore novel pathways linking selected exposures with specific cancers, using emerging multi-omics and genetic data;
- to characterise cancer co-morbidity and investigate underlying mechanisms linking cancer with other diseases.
To address these research questions, we will enhance our existing collaboration with research groups in Oxford (e.g. Million Women Study) and beyond (e.g. WHO-IARC and German Cancer Researcher Center). We will also use data from other cohort studies (e.g. UK Biobank).