Cellular Cannibalism Research Paper

A compendium on Cellular Cannibalism

Introduction
Cellular cannibalism is defined as the ability of a cell to engulf or phagocytise another cell of its own type or any other. It was first described by Leyden in 1904 and referred them as “bird – eye cells”. They are also known as “signet-ring cells”, due to their appearance. [1] [2]
Cannibalistic cells were initially noticed in cytological smears where the cell had ingested another cell – consisted of a vacuole with the ingested cell and this vacuole pushed the nucleus to the periphery. [1]
The word cannibalism is derived from cannibals meaning human eating. The Spanish ‘Carib’ people practised the act of cannibalism, and in Greece the term used is ‘Anthropophagy’ – anthropos means man

A membrane to cytosol framework, including a dynamic link between caveolin-1, ezrin, and actin, plays an important role in formation of the ‘‘cannibalistic vacuole.’’ This connection allows the formation of caveolae enriched endosomes termed as ‘caveosomes’ that seem to represent the driving structure of cannibalism. These caveosomes has a simple and effective digestive machinery consisting of an acidic milieu and a proteolytic enzyme, viz. cathepsin B. [8] [9]

Review of literature
 Sarode et.al [10] identified cannibalistic cells in oral squamous cell carcinoma (OSCC) through routine staining of haematoxylin and eosin, and the same was confirmed through Immunohistochemistry (IHC) analysis.
Their study showed that poorly differentiated OSCC had more cannibalistic cells than moderately differentiated OSCC. Therefore it was concluded that cannibalism quite easily identifiable and could be used as a useful marker in aggressive OSCC.
 Jose D et.al (2014) [11] noted the presence of cannibalistic cells in OSCC. Their study showed the aggressive nature of cancers associated with increase of cannibalistic cells, along with lymph node

in OSCC, wherein one malignant cell was found to engulf another and this complex was further engulfed by another cell. Also it was noted in another area that a single cell engulf two cells simultaneously. As this phenomena was quite different from the traditional cannibalism - Sarode et.al. termed it as “ complex cannibalism”.[6]
Cell in cell Phenomena
Discovery of non – phagocytic cell in cell phenomena could be attributed over a century ago. But its biological significance still remains a mystery. Several scientists over the ages have hypothesised and described various cell in cell phenomena – Steinhaus (1891), proposed cannibalism, Lewis (1925) & Humble et.al (1956) proposed emperipolesis, and recently in 2007, Overholtzer et al discovered ‘ entosis’ – a homogenous cell in cell phenomenon. [15]
Apart from morphological definitions, very little is known and understood about the exact physiology and underlying mechanism of these phenomena, which needs to be explored in future.