Eosinophils and Cancer – Mini Review

The focus of this review is to discuss the role of eosinophils in cancer. A study published in the Journal of Clinical Oncology examined the relationship between eosinophils in peripheral blood and the incidence of colorectal cancer [2]. The researchers found that a higher number of peripheral blood eosinophils were associated with a reduced risk of dying from colorectal cancer, especially in patients who never smoked and in males. Although the study could not identify the mechanism to explain this relationship, one plausible theory is that a more active immune system reduces the risk of developing colorectal cancer. Another study published in the journal Modern Pathology in 2016. Prizement et al. [3] looked at how eosinophils might predict outcomes for patients with colorectal cancer. Taghizadeh et al. [4] found no associations between objective allergy markers and cancer in a total population but reported positivity and a high number of eosinophils with association to reduced risk to die of cancer in specific subgroups. Although staging of colorectal cancer typically is based on information about the tumor itself, lymph node involvement, and the presence of metastases (cancer spread to other sites), often two patients with the same staging will have dramatically different outcome. The authors of this study examined whether eosinophils levels in or around a colorectal tumor helps predict outcome. They concluded that a higher numbers of eosinophils around the primary colorectal tumor were associated with an improved patient outcome, and that they should be routinely counted during tumor examination, it was found that the infiltration of tumors with eosinophils, especially in stromal tissue, may be an important prognostic factor in colorectal cancer.