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Background and AimCancer is one of the foremost causes of morbidity and mortality worldwide. Globally, colorectal cancer (CRC) is the third most diagnosed and fourth most important cause of cancer death. A total of 70% of all CRC‐related deaths occur in low‐ and middle‐income countries. In Sub‐Saharan Africa (SSA), estimating the burden of CRC is difficult. Only 27 of 43 SSA countries have formalized cancer registration systems; data quality is variable and national coverage rare.MethodsThis is a multidisciplinary, longitudinal cohort study started in January 2016. Patients >18 years with histologically confirmed primary adenocarcinoma of the colon and rectum, diagnosed within the previous 12 months, are eligible. Participants were assessed and were followed up for 3 years. Baseline information, including demographics, socioeconomic status, family history, medical and surgical non‐cancer‐related history, dietary history, colonoscopic findings, staging at presentation, treatment, and disease recurrence, is collected, as well as blood tests and histology results. Outcomes include disease recurrence (local and metastatic) and survival.Results and ConclusionThis study aims to describe the clinical presentation, management, and outcomes of adults with CRC in a multiethnic, urban South African population. It will be the first prospective study to describe clinical presentation, demographics, risk factors, treatment, and outcomes according to population group, from both private and state health‐care facilities in Johannesburg, South Africa. The results of this study will be relevant not only to South Africa but also to other SSA countries undergoing similar rates of rapid urbanization and epidemiological transition.

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We are interested in the regulation of early pancreatic differentiation, particularly with regard to factors that enhance insulin cell proliferation. Both retinoic acid and insulin-like growth factor 1 (IGF-1) are known to be important in the proliferation and differentiation of insulin cells. Individually, they have the ability to increase the proportion of insulin cells when added to cultures of chick dorsal pancreatic buds. The aim of this study was to define the action of retinoic acid (RA) in combination with IGF-1 on the proportion of insulin cells. The dorsal pancreatic bud of 5-day-old chick embryos was excised and the endodermal component, with minimal adherent mesenchyme, was explanted onto Matrigel. RA (10^–6 M) and IGF-1 (50 ng/ml) were added to Ham’s F12 culture medium containing transferrin (5 µg/ml) and selenium (10^–10 M) (F12.TS). Control explants were cultured in F12.TS alone or in F12.TS containing dimethyl sulphoxide (DMSO) [F12.TS (DMSO)]. After 7 days in culture, insulin and glucagon cells were localized immunocytochemically; numbers of insulin cells were expressed as a percentage of insulin plus glucagon cell counts. Addition of RA plus IGF-1 to the medium increased the proportion of insulin cells markedly (23.43%) compared with the proportions in control explants (11.3% with F12.TS (DMSO), 13.2% with F12.TS). This increase represents a more than twofold increase in the proportion of insulin cells over that of control explants.

We assessed the potential role of all-trans-retinoic acid on the developing chick pancreas, specifically with regard to the proportions of insulin cells. The endodermal component of the dorsal pancreatic bud of 5-d-old chick embryos was cultured on Matrigel. Retinoic acid (10(-6) or 10(-5) M) was added to a standard serum-free medium, Ham's F12 containing insulin, transferrin and selenium (F12.ITS). Control grafts were cultured in F12.ITS alone or in F12.ITS with DMSO (the diluent for retinoic acid). After 7 d the explants were retrieved, freeze-dried, vapor-fixed, and embedded in resin. Endocrine cell types were identified by immunocytochemistry. The numbers of insulin cells were expressed as a proportion of the sum of insulin plus glucagon cells. Retinoic acid had a dose-related effect; the proportion of insulin cells in explants treated with the lower dose of retinoic acid (10(-6) M) was more than twice the proportion of insulin cells in explants treated with the higher dose (10(-5) M) of retinoic acid and more than three times that of the control grafts.

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