1- Introduction
2- Tumour-Associated Macrophage (TAM)
3- Phenotypical Distinction of Macrophage Subtypes
4- TAM in Colon Tumour
5- Potential Candidates to Reeducate TAM
6- Conclusion
References
Introduction
Colorectal cancer (CRC), also known as bowel cancer or colon cancer, is a type of cancer that begins its abnormal cell growth in the colon or rectum part of the large intestine. In men, CRC has been reported to be the third most common case to occur. On the other hand, it is the second most commonly occurring cancer incidence among women in the world [1, 2]. According to Ferlay et al. [3], approximately 1.36 million people around the world have been affected with cancer. As shown in Table 1, in the United States of America (USA) alone, it is estimated that about 71,420 and 64,010 new CRC cases will be reported among males and females, respectively [4]. Meanwhile, in Asian countries, the disease has become one of the major health concerns in which the number of CRC cases being reported is increasing in an alarming state [5]. Among Asian countries, Japan has been recorded to have the highest incidence of CRC, followed by Hong Kong [6, 7]. Malaysia, in particular, has categorised CRC to be its second most common cancer reported. Table 2 shows that ethnic Chinese holds the highest incidence rate per 100,000 (27.35), followed by Malay (18.95), and Indian (17.55) [8]. Several risk factors have been identified to be associated with the development of CRC. Obesity, lack of physical activity, tobacco use, moderate-to-heavy alcohol consumption, hypertension, abnormal blood lipids, and colonisation of Streptococcus gallolyticus (S. gallolyticus) are said to be the exogenous risk factors. Conversely, personal or familial history of colorectal polyps, inherited CRC syndromes (e.g., hereditary nonpolyposis colon cancer (HNPCC) and Cowden’s disease), inflammatory bowel disease, and type 2 diabetes are said to be the endogenous risk factors [9–11]. As shown in Figure 1, in the presence of exogenous and/or endogenous risk factors, cancer development might occur if the risk factors managed to interact synergistically [12].