Aim: A confirmed wild-type RAS tumor status is commonly required for prescribing anti-EGFR treatment for metastatic colorectal cancer. This noninterventional, observational research project estimated RAS mutation prevalence from real-world sources. Materials & methods: Aggregate RAS mutation data were collected from 12 sources in three regions. Each source was analyzed separately; pooled prevalence estimates were then derived from meta-analyses. Results: The pooled RAS mutation prevalence from 4431 tumor samples tested for RAS mutation status was estimated to be 43.6% (95% CI: 38.8-48.5%); ranging from 33.7% (95% CI: 28.4-39.3%) to 54.1% (95% CI: 51.7-56.5%) between sources. Conclusion: The RAS mutation prevalence estimates varied among sources. The reasons for this are not clear and highlight the need for further research. Colorectal cancer (CRC) was the third most common malignancy among men and the second most common malignancy among women globally in 2012 [1]. Approximately, 60% of CRC cases occur in developed regions and incidence rates can vary up to tenfold around the world, with the lowest rates observed in South Central Asia and Africa (excluding Southern Africa) [2]. A quarter of patients with CRC already have metastatic disease at the time of their initial presentation and diagnosis, and almost 50% will subsequently develop metastases [3]. Once

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