Correlative Research Of The Pathologic Features Of Invasive Micropapillary Carcinoma Of The Breast

[Objective]To investigate the relationship between lymph node metastasis and pathologicfeatures of invasive micropapillary carcinoma (IMPC) of the breast.[Methods]Primary pathologic features and lymph node metastasis of fifty-one cases of IMPCwere examined by microscopic analysis. Immunohistochemical analysis for vascularendothelial growth factor (VEGF)-C and VEGF receptor (VEGFR)-3 was performed,and lymphatic vessel density was measured on these cases.[Results]1. The number of positive lymph nodes in the group of IMPC histologic gradeⅡ/Ⅲ(mean 12.5) was significantly more than that in the group of histologicgradeⅠ(mean 4.0)(P＜0.05).2. The incidence of nodal metastases in the group of lymphocyte infiltration(+)/(++)(96.4%) was significantly higher than that in the group of(-)/(±)(60.9%)(P＜0.01); and the number of metastatic nodes (mean 14.4) wasalso significantly more in the group of lymphocyte infiltration (+)/(++)compared with that in the group of (-)/(±)(mean 4.6)(P＜0.01).3. VEGF-C expression correlated positively with histologic grade (P＜0.01) andwas at a significantly higher level in cases with histologic gradesⅡandⅢcompared with cases with a histologic grade ofⅠ(P＜0.05 and P＜0.01,respectively). VEGF-C expression also was correlated positively with thelymph node metastasis (P＜0.05); lymphatic vessel density was positivelycorrelated with VEGF-C expression (P＜0.01) and lymph node metastasis(P＜0.01).4. Tumor size was not correlated with lymph node metastasis (P＞0.05). 5. The percentage of IMPC in the tumor is not associated with its lymph nodemetastasis (P=0.932). The metastatic foci in lymph node were all IMPC ormainly IMPC.6. Fourteen of twenty-eight cases of IMPC containing ductal carcinoma in situ(DCIS) were DCIS ofmicropapillary type (14/28cases, 50%).[Conelusions]1. The histologic grade, lymphatic vessel density and lymphocyte infiltration ofIMPC may be the key factors that influence its lymph node metastasis.2. Higher expression of VEGF-C and VEGFR-3 play an important role inpromoting lymph node metastasis of IMPC.3. It is not the tumor size or the amount of IMPC component in the tumor, butthe IMPC histologic features and stromal reactions that correlate with theaggressiveness of the tumor.4. Intermediate-or high-grade DCIS with a micropapillary pattern may be theearly stage of IMPC. [Objective]To study and research the significance of the lymphocytes infiltrating in the tumormicroenvironment of invasive micropapillary carcinoma (IMPC) of the breast deeply.To investigate the significance and molecular mechanism of lymphocyte infiltrationin the tumor microenvironment of different types of breast carcinomas, and to explorethe reason of some tumors in which dense lymphocyte infiltrating but with poorprognosis, by contrasting the lymphocyte infiltrating IMPC with prominentlymphocyte infiltration, medullary carcinoma (MC) and atypical MC (AMC) of thebreast that all with anaplastic morphology and dense lymphocytic infiltrate.[Methods]1. 28 cases of IMPC with prominent lymphocyte infiltration, 29 cases of MC and 35cases of AMC were selected, and the distribution of tumor infiltratinglymphocytes (TILs) in the three kinds of tumors was examined by microscopy.2. Immunohistochemical analysis for CD3, CD4, CD8, CD20, CD56, Fas and FasLwas performed, and the types and distribution of TILs in the three kinds of tumorswas measured.3. Double immunohistochemical staining for Fas, FasL and CD4, CD8 wasperformed respectively in the three kinds of tumors to investigate the type anddistribution of T lymphocyte in the cases in which tumor cells were positive forFas and/or FasL.4. The expressions of CD8/Perforin, CDS/Granzyme B, CDS/Fas and CDS/FasLwere evaluated in the three kinds of tumors using double immunofluoresceinstaining with a laser scanning confocal microscope (LSCM) to investigate thedistribution and percent of active CD8~+T lymphocytes in the cases with CD8~+Tlymphocytes (cytotoxic T lymphocyte, CTL).[Results] 1. The distribution of TILs in the three kinds of tumors was different. Most ofTILs were lymphocytes infiltrating tumor stroma (stromal) in IMPC withprominent lymphocyte infiltration, but most of TILs were lymphocytesinfiltrating tumor nests (intraepithelial) in MC and AMC.2. In the three kinds of tumors, the positive degree of CD3~+T lymphocytes wassignificantly higher than that of CD20~+B lymphocytes (P＜0.01). In MC,AMC and IMPC, the positive degree of CD8~+T lymphocytes was significantlyhigher than that of CD4~+T lymphocytes (P＜0.01). There were only 2 cases ofMC, 1 case of AMC and 1 case of IMPC with few CD56~+ NK cells infiltration.3. In MC and AMC, the expression of Fas in tumor cells and expression of FasLin lymphocytes were significantly higher than that in IMPC (P＜0.01,respectively). Most of these lymphocytes were CD8~+T cells infiltrating tumornests by double immunohistochemical staining. In IMPC, the expression ofFasL in tumor cells and expression of Fas in lymphocytes were higher thanthat in MC and AMC, but there was no statistic significance (P＞0.05), andmost of these lymphocytes were CDS~+T cells infiltrating tumor stroma.4. Using double immunofluorescein staining with a laser scanning confocalmicroscope (LSCM), in MC and AMC, the fluorescent positive area of CD8~+Tcells was larger, and the percent of Perforin~+CD8~+, Granzyme B~+CD8~+,FasL~+CD8~+ in CD8~+T cells were significantly higher than that in IMPC(P＜0.05), and most of these lymphocytes were CD8~+T cells infiltrating tumornests. In IMPC, the percent of Fas~+CD8~+ in CD8~+T cells were higher than thatin MC and AMC, but there was no statistic significance (P＞0.05), and most ofthese Fas~+CD8~+ cells were lymphocytes infiltrating tumor stroma.[Conclusions]1. There were both T and B lymphocytes infiltration in the tumor microenvironment of the three kinds of tumors, but most of TILs were Tlymphocytes in which CD8~+T cells (CTL) were the main lymphocytes. Therewere scarce NK cells infiltration in the three kinds of tumors.2. The distribution of TILs in the three kinds of tumors was different. Most ofTILs were lymphocytes infiltrating tumor stroma (stromal) in IMPC withprominent lymphocyte infiltration, but in MC and AMC, most of TILs werelymphocytes infiltrating tumor nests (intraepithelial) that was favourable forthe TILs to play the effect of anti-tumors.3. In MC and AMC, there were plenty of CDg~+ CTL infiltrating tumor nests,they secreted Perforin and Granzyme B to dissolve the tumor cells, but thecell toxic action of CTL was weak in IMPC, which might be one of thereasons that the prognosis was poor regardless of plenty of lymphocytesinfiltrating in IMPC.4. In MC and AMC, there were plenty of FasL~+CTL infiltrating Fas~+ tumor nests,they induce the apoptosis of tumor cells; but in IMPC, FasL~+CTL werefewer and infiltrating tumor stroma, and the expression of Fas in tumor cellswas weak, that was unfavourable for CTL to induce the apoptosis of tumorcells, which might be another reason that the prognosis was poor regardless ofplenty of lymphocytes infiltrating in IMPC.5. In IMPC, tumor cells might avoid the attack of lymphocytes by downregulation of the expression of Fas, and induce the apoptosis of Fas~+lymphocytes by increasing the expression of FasL on the same time, whichmight be also one of the reasons that the prognosis was poor regardless ofplenty of lymphocytes infiltrating in IMPC.6. The TILs infiltrating in the tumor microenvironment of IMPC had differentfunction and active state from MC and AMC, so the significance of TILs for prognosis might be different between IMPC and MC, AMC.