B-vitamins attenuates preliminary steps of hyperhomocysteinemia and colorectal cancer

Cancer is second leading cause of death worldwide, accounting for an estimated 9.6 million deaths in year 2018, from which 70% death occurred in low- and middle-income countries. World Health Organization estimates that there will be 20 million new cases and 12 million deaths from cancer alone by the year 2020 [1]. Furthermore, the WHO reported that in Western countries, the rate of colorectal cancer (CRC) has increased dramatically as compared to other types of cancers, and this increase was attributed to westernization in food choices and dietary pattern as well as adopting a sedentary lifestyle [1, 2]. CRC is the third most common cancer and a major cause of cancer mortality and over 1.8 million cases were reported during 2018. Although the introduction of colonoscopy techniques has made it easier to diagnose CRC at an early stage, in most of the cases it can occur due to sporadic tumorigenesis via the adenoma-carcinoma sequence [3, 4]. Chronic inflammation is implicated in causing cancer and the process can take years to develop CRC [5]. An early screening will therefore allow in making an advance action plan for CRC diagnosis, which will not only help to reduce health cost for secondary treatments but will also support to improve the efficiency of country's work force. Although the CRC cases in the USA have dropped by 30% during the last decade, the CRC cases in the Arab world have increased [6, 7]. Hyperhomocysteinemia (HHcy) is an independent risk factor of coronary heart disease, stroke, peripheral vascular diseases, and cancers [8]. HHcy induces cancer by cellular oxidative stress, through oxidant-mediated responses, and epigenetic modifications such as alterations of DNA methylation and their regulatory role in gene expression. High levels of plasma homocysteine levels have been observed in cancer patients, indicating its association with venous and arterial thrombosis [9]. Venous thromboembolism is the second most common cause of death in cancer patients [10].