Expression And Its Significance Of ERK5 In Human Rectal Adenocarcinoma

Extracellular-signal-regulated kinase 5 (ERK5) is a member of the mitogen-activated protein kinase (MAPK) family and it is the most recently discovered member of the family.ERK5, also known as big MAP kinase 1 (BMK1),is an atypical MAPK pathway.It is expressed in a variety of tissues and is activated by a range of growth factors, cytokines and cellular stresses.It is critical for cell proliferation,cell differentiation, cell motility, apoptosis and gene regulation.It has been confirmed that ERK5 plays a critical role in a variety of physiological processes such as the differentiation of skeletal muscle cells, cardiac development,vascular maturation/angiogenesis and neural differentiation.Hyperactivity of the ERK5 pathway is associated with highly aggressive forms of diseases such as Diabetes Mellitus(DM) and cancer.To investigate the relationships between the expression of ERK5 and normal tissues near the adenocarcinoma, rectal adenoma, rectal adenocarcinoma, and the clinical pathological parameters of rectal adenoma and adenocarcinoma.Then explore the functions of ERK5 in the occurence and development of rectal adenocarcinoma.40 rectal adenocarcinomas,30 rectal adenomas and 40 normal tissues near the rectal adenocarcinoma obtained in operations in the 2nd Xiangya hospital of Central South University from December 2008 to January 2010 were stained by S-P immunohistochemical staining to investigate the expression of ERK5 in rectal adenocarcinoma, rectal adenomas, normal tissues near the adenocarcinoma,through which we analyse the relationship between ERK5 and the clinical pathological parameters of rectal adenoma and adenocarcinoma.1.In 40 cases of rectal adenocarcinoma,positive expression of ERK5 is 26 cases(65.0%);40 cases of normal rectal tissues near the cancers, positive expression of ERK5 is 14 cases(35%);30 cases of rectal adeomas,positive expression of ERK5 is 12 cases(40.0%).In rectal adenocarcinomas,positive expression of ERK5 is significantly higher than that in normal rectal tissues near the adenocarcinoma (χ2=7.200,p<0.01),and also than that in rectal adenomas(χ2=4.317,p<0.05),however,positive expression of ERK5 between normal rectal tissues near the cancers and benign rectal lesions has no apparent differences(χ2=0.184, p>0.05).2.Positive expression of ERK5 has no relationships with the adenomas' size or patterns, or the patients' gender and age,however,the expression of ERK5 has relationship with the adenomas' atypical hyperplasia(p<0.05).Positive expression of ERK5 has no apparent differences between the mild hyperplasia and the moderate hyperplasia,and between the moderate hyperplasia and the severe hyperplasia(p>0.05),but positive expression of ERK5 in the severe hyperplasia is significantly higher than that in the mild hyperplasia(p<0.05).3.Positive expression of ERK5 has relationships with the stages,depth of invasion and nodular metastasis of the adenocarcinoma,but it has no relationship with the tumor differentiation or tumor size, or the patients' gender and age.Positive expressions of ERK5 of Dukes' A,B,C are 20.0%,61.5%,94.1%, and the differences are statistically significant(χ2= 15.305, p=0.000).Positive expression of ERK5 of outside or on the serosa is significantly higher than that of inside the serosa (χ2=8.120, p<0.01),and the positive expression of ERK5 of positive nodular metastasis is significantly higher than that of negative nodular metastasis(χ2=11.018, p<0.01),however,the expression of ERK5 has differences in tumor differentiation,tumor size,the patients' gender and age,but they are not statistically significant (p>0.05).1.ERK5 may contribute to the occurence and deveopment of rectal adenocarcinoma.2.Detection of the expression of ERK5 maybe helpful in the diagnosis and prognosis for rectal adenocarcinoma.