The Differences Of Characteristics Of Autofluorescence Spectrum Between Normal And Micrometastatic Lymph Nodes In Colorectal Carcinoma And Its Possible Mechanism

Objective: To investigate the correlation of collagenⅣexpression, MMP-9 expression and differential autofluorescence intensity in normal and micrometastatic lymph node in patients with colorectal carcinoma and its possible mechanism.Methods: "Laser-induced autofluorescence analyses system" was used to detect the autofluorescence of 100 lymph nodes in 25 patients with colorectal carcinoma. In all the samples, expression of collageⅣand MMP-9 was detected with immunohistochemical staining. Additionally, MMP-9 mRNA was also detected with RT-PCR. Correlations of the results were studied.Results: Autofluorescence peak intensity at 460nm in micrometastatic lymph nodes was lower than that in normal lymph nodes of the same patient, which had statistical significance(P＜0.05). Moreover, difference of autofluorescence peak intensity between micrometastatic lymph nodes and corresponding normal ones increased, accompanied with the decrease of collagenⅣexpression in micrometastatic lymph nodes. Meanwhile, there was negative correlation between the expression of MMP-9 and collagenⅣ.Conclusions: 1. There is no difference between autofluorescence analysis and pathological biopsy when detect micrometastasis in lymph nodes in colorectal carcinoma patients. 2. Autofluorescence peak intensity at 460nm is statistically different between micrometastatic lymph nodes and corresponding normal ones in colorectal carcinoma patients. 3. Decrease of collagenⅣin micrometastatic lymph nodes may be one reason of the different Autofluorescence peak intensity in micrometastatic and normal lymph nodes. 4. Different expression of MMP-9 is another reason for the different Autofluorescence peak intensity in micrometastatic and normal lymph nodes.