Macrophage Invasion Of Tumor Cell Islets Predict Good Prognosis In Lung Cancer

Objective:To detect the infiltration of macrophage in lung cancer and benignlesions, and evaluate its correlation with clinicopathologic characteristics oflung cancer and its prognostic significance.Methods:The tissues from surgically resected 146 cases of lung cancer and 20cases of lung benign lesions were examined by immunohistochemical SPmethod using monoclonal antibody to CD68. All statistical analyseswere performed by SPSS 13.0.Results:(1) CD68~+ macrophages were detected in both lung cancer tumor-cellislets (median, 3. 8 cells/×400; range, 0.2 to 179) and stroma(median, 6cells/×400; range, 0.2 to 142). CD68~+ macrophages were detected in the lungbenign lesion(median, 29.2 cells/×400; range, 26.2 to 33.4). Macrophagecounts in tumour stroma and islets of lung cancer were lower than those ofbenign lesion (P＜0.05); Macrophage counts in tumour islets were lower thanthose in tumour stroma (P＜0.05). (2) Macrophage tumour islets/stromal ratio and tumour isletsmacrophage counts were inversely correlated with stages; Tumour stromalmacrophage counts were positively correlated with stages; Tumour isletsmacrophage counts with lymph nodes metastasis were lower than thosewithout lymph nodes metastasis(P＜0.05). Tumour stromal macrophagecounts with lymph nodes metastasis were higher than those without lymphnodes metastasis, but not significantly(P＞0.05).(3) An inverse correlation between stromal macrophage counts andpatient survival was present (r_s=-0.187; P＜0.05); While it was a positivecorrelation between tumor cell islet macrophage counts and survival(r_s=0.510; P＜0.01), as well as between macrophage tumor islets/stromalratio and survival (r_s=0.633; P＜0.001).(4) The log-rank statistics was used to compare survival rates. There wasan inverse association between survival rates and stromal macrophagecounts(5-year survival was 18.9% versus 44.4%)(P＜0.01), and strikingpositive associations between survival rates and both tumor islet-cellmacrophage counts(5-year survival was 51.4% versus 11.1%)(P＜0.001) andtumor macrophage islet/stromal ratio(5-year survival was 58.1% versus 4.2%)(P＜0.001).(5) Using multivariate Cox proportional hazards analysis, increasingtumour islet macrophage counts(P＜0.001) and Tumour islet/stromalmacrophage ratio(P＜0.001) emerged as favorable independent prognosticindicators; In contrast, increasing tumour stromal macrophage counts was anindependent predictor of reduced survival(P＜0.05). Conclusions:(1) Macrophage infiltrted within tumour stromal and islets in lungcancer may serve as two roles:macrophage in tumor islets had theanti-tumour immune response; but those in stromal macrophage maypotentially promote the tumor growth and metastasis of lung cancer.(2) Increasing tumour islet macrophage counts and tumour islet/stromalmacrophage ratio emerged as favorable independent prognostic indicators;This has important implications to adjuvant therapy of lung cancer.