ABSTRACT
Some invasive breast carcinomas are surrounded by a clear space that separate the tumor cells from the adjacent stroma, similar to invasive micropapillary carcinoma (IMPC), but lack the thin strands of connective tissue that separate the cells and characteristic "inside-out" growth pattern of IMPC on immunohistochemical stain for EMA. We consider the presence of the retraction clefts a common phenomenon that may present as a precursor stage of IMPC (PSIMPC). In this study, a total of 2497 cases of invasive breast carcinomas were prospectively collected. Among 2497 cases of breast cancer, 949 (38.0 %) cases were PSIMPC, 200 (8.0 %) cases were IMPC and 1348 (54.0 %) cases were IBC-NST. LVI was seen in128 of 200 (64 %) IMPC and 364 of 948 (38.0 %) PSIMPC, in contrast to 246 of 1341 (18 %) IBC-NST (P < 0.001). Lymph node metastasis was seen in 147 of 200 (73.4 %) IMPC and 551 of 949 (58 %) PSIMPC, in contrast to 563 of 1345 (42 %) IBC-NST (P < 0.001). The 5-year disease-free survival (DFS) and overall survival (OS) of PSIMPC were 76.8 % and 87.6 %, compared to 63.2 % and 85.9 % in IMPC, 86.2 % and 93.7 % in IBC-NST. PSIMPC demonstrated a more favorable DFS and OS compared to IMPC, but worse DFS and OS compared to IBC-NST. Cox and logistic regression analysis showed that PSIMPC was an independent predictor of DFS and OS. Our findings suggest that the presence of retraction clefts is a precursor state of IMPC, exhibiting IMPC-like features, such as higher incidence of lymphovascular invasion, lymph node metastasis and more aggressive clinical behavior.
Subject(s)
Breast Neoplasms , Carcinoma, Ductal, Breast , Carcinoma, Papillary , Carcinoma , Humans , Female , Lymphatic Metastasis , Breast Neoplasms/pathology , Carcinoma, Papillary/pathology , Disease-Free Survival , Carcinoma, Ductal, Breast/pathologyABSTRACT
Invasive micropapillary carcinoma (IMPC) has very high rates of lymphovascular invasion and lymph node metastasis and has been reported in several organs. However, the genomic mechanisms underlying its metastasis are unclear. Here, we perform whole-genome sequencing of tumor cell clusters from primary IMPC and paired axillary lymph node metastases. Cell clusters in multiple lymph node foci arise from a single subclone of the primary tumor. We find evidence that the monoclonal metastatic ancestor in primary IMPC shares high frequency copy-number loss of PRDM16 and IGSF9 and the copy number gain of ALDH2. Immunohistochemistry analysis further shows that low expression of IGSF9 and PRDM16 and high expression of ALDH2 are associated with lymph node metastasis and poor survival of patients with IMPC. We expect these genomic and evolutionary profiles to contribute to the accurate diagnosis of IMPC.
Subject(s)
Aldehyde Dehydrogenase, Mitochondrial/genetics , Breast Neoplasms/genetics , Carcinoma, Papillary/genetics , DNA-Binding Proteins/genetics , Immunoglobulins/genetics , Lymphatic Metastasis/genetics , Nerve Tissue Proteins/genetics , Transcription Factors/genetics , Aldehyde Dehydrogenase, Mitochondrial/metabolism , Breast Neoplasms/metabolism , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Carcinoma, Papillary/metabolism , Carcinoma, Papillary/mortality , Carcinoma, Papillary/pathology , DNA-Binding Proteins/metabolism , Evolution, Molecular , Female , Gene Dosage , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Immunoglobulins/metabolism , Multigene Family , Neoplasm Invasiveness , Nerve Tissue Proteins/metabolism , Signal Transduction , Survival Analysis , Transcription Factors/metabolismABSTRACT
PURPOSE: Invasive micropapillary carcinoma (IMPC) of the breast has distinct histological features and molecular genetic profiles. Gains/amplifications of 8q24 are found associated with IMPC. Although the prostate stem cell antigen (PSCA) gene is located at chromosome 8q24, and found over-expressed in prior studies, its prognostic values and biological significance in IMPC have not been well studied. METHODS: Fluorescence in situ hybridization (FISH) was used to assess the frequencies of PSCA copy number gains in IMPC, invasive ductal carcinoma of no special type (IDC-NST), and invasive lobular carcinoma (ILC) samples. The protein expression levels of PSCA were examined in 56 IMPC, 72 IDC-NST, and 56 ILC samples using immunohistochemical analysis. RESULTS: PSCA gene amplification was detected in 45.2% (14/31) of the IMPC, 28.1% (9/32) of the IDC-NST, and none (0/25) of the ILC. PSCA protein expression was observed in 58.9% (33/56), 40.3% (29/72), and 3.6% (2/56) of IMPC, IDC-NST, and ILC samples, respectively. The concordant rate of the immunohistochemistry and FISH data was 85.2%. PSCA gene amplification highly correlated with its protein overexpression (rs = 0.687, P < 0.001), suggesting that gene amplification is an important mechanism involved in PSCA overexpression. Our univariate analysis showed that the patients with PSCA-positive IMPC had a decreased disease-free survival (DFS) compared to PSCA-negative IMPC patients (P = 0.003). Our multivariate analysis confirmed the worse DFS in PSCA-positive IMPC patients (P = 0.022). CONCLUSIONS: Our results indicate that PSCA may be an attractive target in the 8q24 amplicon and that it may serve as a molecular marker of metastasis and recurrence in IMPC. The differential expression of PSCA may be associated with cell adhesion. Detection of PSCA protein and gene amplification may help manage and predict the prognosis of IMPC patients.
