Expression Of NGAL And NGALR And Their Clinical Significance In Colorectal Adenocarcinoma

PurposeTo observe the expression of neutrophil gelatinase-associated lipocalin (NGAL) and its receptor (NGALR) in colorectal adenocarcinoma specimens, analyze the relationship between the clinicopathological characters of colorectal adenocarcinoma and two factors, further to investigate the relationship between expression of these two proteins and tumor progression.Methods(1)The expression of NGAL and NGALR proteins was detected in40cases of adjacent normal colorectal mucosa,40cases of adenomas and96cases of colorectal adenocarcinoma by immunhistochemical staining (streptavidine-peroxidase method).(2)RT-PCR was used to observe the expression of NGAL mRNA and NGALR mRNA in20cases of the normal colorectal mucosa,5cases of adenomas and20cases of colorectal adenocarcinoma.Results(1)The positive expression rate of NGAL and NGALR in colorectal adenocarcinoma tissues was49.0%and35.4%, respectively, significantly higher than that in normal colorectal mucosa and adenomas tissues(P<0.05). The mRNA of NGAL and NGALR in colorectal adenocarcinoma was significantly higher than that of both colorectal adenomas and normal mucosa(P<0.05).(2)The expression of NGAL was associated with invasion, distant metastasis and TNM stages (P<0.05), but not associated with patient’s age, gender, tumor size, histological grade and lymph node metastasis in colorectal adenocarcinoma (P>0.05).(3)The expression of NGALR was associated with tumor differentiation, depth of invasion, distant metastasis and TNM staging (P<0.05), but not associated with patient’s age, gender, tumor size and lymph node metastasis in colorectal adenocarcinoma (P>0.05).(4)Co-expression of NGAL and NGALR was significantly correlated with histopathology, lymph node metastasis, distant metastasis and TNM stages (P<0.05), but not associated with patient’s age, gender and tumor size in colorectal adenocarcinoma (P>0.05).(5)The expression rate of NGAL and NGALR was positive related in colorectal adenocarcinoma (rs=0.364, P<0.001).Conclusion(1) The protein and mRNA expression levels of NGAL and NGALR are frequently upregulated in colorectal adenocarcinoma, whereas normal and adenoma tissues show negative or weak expression. This suggests that NGAL and NGALR may associate with occurrence of colorectal cancer.(2) Overexpression of NGAL and NGALR are closely associated with histopathologic grading and metastasis in colorectal adenocarcinoma. This suggests that NGAL and NGALR may play a key role in development, invasion and metastasis of colorectal adenocarcinoma.(3) Co-expression of NGAL/NGALR is significantly correlated with histopathology, lymph node metastasis, distant metastasis and TNM stages, may represent a more malignant phenotype in colorectal adenocarcinoma. This indicates that colorectal adenocarcinoma with co-expression NGAL/NGALR may be of higher degree of malignancy.(4) Positive correlation between NGAL and NGALR expression in colorectal adenocarcinoma indicates that their expression may exist within a kind of synergy. Combined detection of NGAL and NGALR will contribute to the clinical diagnosis and efficacy evaluation of colorectal cancer.