Differences in tumor angiogenesis and related factors between lung adenocarcinomas manifesting as pure ground glass opacity and solid nodules.

INTRODUCTION

The prognosis of ground glass opacity featured lung adenocarcinomas (GGO-LUAD) is significantly better than that of solid nodule featured lung adenocarcinomas (SN-LUAD), but the specific reasons behind their indolent tumor behavior are still unclear. The purpose of this study is to investigate their differences in intratumoral microvessels, related angiogenic factors and important stromal cells.

METHODS

Thirty patients (15 paired patients only with GGO or SN) diagnosed with pathological stage 0-I lung adenocarcinoma who underwent surgical treatment were included into this study. Immunohistochemistry was performed to stain the blood vessel markers (CD31, CD34 and CD105), LYVE-1, the cancer-associated fibroblasts (CAFs) markers (α-SMA and S100A4), TGF-β and HIF-1α from 30 patients tissue sections. At the same time, Ki67 Labeling Index (LI) extracted from pathological report of all patients was also analyzed.

RESULTS

GGO-LUAD is more abundant than SN-LUAD in lymphatic vessel density (LVD), but similar in total microvessel density (CD31 + MVD). However, GGO-LUAD is significantly lower than SN-LUAD in CD34 + MVD and CD105 + MVD. In terms of TGF-β, HIF-1α expression and Ki67 LI level, GGO-LUAD was also significantly weaker than SN-LUAD. Moreover, the distribution of CAFs in GGO-LUAD is less than that in SN-LUAD. Regardless of the pathological type (adenocarcinoma in situ (AIS) or minimally invasive adenocarcinoma (MIA) or invasive lung adenocarcinoma (IAC)), there is no difference in any of the above indicators in GGO-LUAD.

CONCLUSIONS

Our finding displays that GGO-LUAD was significantly lower than SN-LUAD in CD34 + MVD and CD105 + MVD reflecting tumor angiogenesis, and the distribution of CAFs and factors related to tumor angiogenesis were also significantly lower in GGO-LUAD, which may indicate that the weak ability of angiogenesis might be the reason for the good prognosis of GGO-LUAD.