Centrosomes Refer to the Region of Animal

Centrosomes refer to the region of animal cell cytoplasm which is located near the cell's nucleus and contains centrioles. It major role is noted to be the organization of the microtubules. Recently, there has been a lot of literature purporting that there could be a link between centrosomes and cancer. The exact roles of centrosomes in cancer progression are the subject of this discussion. The centrosome has been regarded as the part of the cell which is responsible for chromosomal stability (Khong, Zhang and Zhao,2004)

Chromosomal instability is a term which is defined as the continuous change in the cell's transcriptional capacity which is caused by the changes in the structure as well as number of chromosomes and has received a growing level of appreciation in academia in the understanding of the specific cellular mechanisms responsible for tumorigenesis (Saunders,2005).

The role of centrosome in the development of cancer

The work of Khong, Zhang and Zhao (2004) which was dedicated to the investigation of the role of centrosome in the development of cancer indicated that the accumulation of a set of genetic alterations that involve the activation of the proto-oncogenes as well as the inactivation of the tumor suppressor genes have for along time been noted to be the main driving forces behind the phenomenon of carcinogenesis. Cancer can therefore be considered a genetic abnormally which is caused by damage to the DNA structure and functions. Even though the molecular etiology is largely enigmatic, recent research outcomes indicates that the centrosome while acting together with the centrioles and the connecting microtubules (filaments) can be viewed as the "brain" of a given cell. This is due to the fact that they are responsible for the maintenance of genetic stability as well as the coordination of several other cellular activities. Therefore, any abnormally affecting the centrosomes may result in the unequal/unusual chromosome segregation that would result in genetic alterations such as cancer.

The role of centrosomes amplification in cancer development and progression'

Extant literature indicates that centrosome amplification is the origin of the chromosomal instability that leads to the development of tumor. This notion was initially suggested by Theodor Boveri about a century ago. The role of the noted centrosome amplification in the development of cancer is however a subject of controversy. The centrosome is implicated due to the outcome of several studies that seemed to suggest and show evidentially that the pathways of cell cycles do converge on the centrosome an organelle that is noted to be in control of the progression of the cell cycle.

The centrosome is noted to influence the structure of the cell via the process of nucleation as well as the organization of the cytoplasmic mictotubules as noted by Kirschner and Mitchison (1986). As mentioned earlier, centrosome amplification has been implicated severally in the pathogenesis of cancer (Weber et al., 1998, Pihan et al., 1998, Kuo et al., 2000). Centrosome multiplication is a term commonly used to signify the centrosomes that normally appear in larger sizes than usual. The amplified centrosomes are noted by Lingle et al. (1998) to show elements of protein hyperphosphorylation as well as altered functional properties like increase capacity of the microtubule nucleating as further indicated in the work of Miyoshi et al., (2001).

Images from electron microscope reveals supernumerary centrioles in centrosomes of tumors affecting human and animals. These include thymic carcinoid, leiomyosarcoma, glioma and neuroblastoma tumors (Kaneko et al., 1980, Ring, 1982).

Systematic analyses of various centrosomes extracted from human breast carcinomas as well as house models for cancer (prostate) indicated a wide range of anomalies in the structure of the centrosome. Such anomalies include excessive number of centrioles, inverted centrosome polarity location, abnormal orientation of the centriole as well as an increased material of the pericentriolar region (Schatten et al., 2000).These structural abnormalities in the centrosome have therefore been implicated as the main possible cause of cell and tissue architecture loss as seen in cases of cancer (anaplasis) via the alteration of the functions of centrosome function in correlation with the elements of chromosome implication, chromosomal instability as well as aneuploidy.

The evidence that the chromosome defects are a factor in the genesis of tumor phenotypes

Aneuploidy which is a form of cellular genomic instability and is characterized by the gains as well as losses of the entire array of chromosomes is noted to occur in the early months of the development of tumor phenotypes. This suggests that it may play a role in tumor progression as well as tumorigenesis. It is further noted that aneuploidy is usually present in a majority of malignant tumors as opposed to the benign ones which are noted by D'Assoro, Lingle, Salisbury (2002). Aneuploidy can therefore be concluded to lead to the cases of phenotypic heterogeneity in cases of cancer. This reflects the persistent and slow generation of new chromosomal variations as noted by Mitelman (1994).