Cell polarity and cell adhesion associated gene expression differences between invasive micropapillary and no special type breast carcinomas and their prognostic significance

The differences between pure and mixed invasive micropapillary breast cancer: the epithelial-mesenchymal transition molecules and prognosis

PURPOSE

Invasive micropapillary carcinoma (IMPC) of the breast is known for its high metastatic potential, but the definition of pure and mixed IMPC remains unclear. This retrospective cohort study aims to investigate the prognostic significance of the micropapillary component ratio and the expression of critical molecules of epithelial-mesenchymal transition (EMT), including E-cadherin (E-cad), N-cadherin (N-cad), CD44s, and β-catenin (β-cat), in distinguishing between pure and mixed IMPCs.

METHODS

We analyzed 100 cases of locally advanced IMPC between 2000 and 2018 and excluded patients who received neoadjuvant chemotherapy. Pure IMPC was defined as having a micropapillary component of over 90%. A comprehensive recording of prognostic parameters was conducted. The IMPC areas were analyzed using the immunohistochemical (IHC) staining method on the microarray set for pure and mixed IMPC patients. Pearson's chi-square, Fisher's exact tests, Kaplan-Meier analysis, and Cox proportional hazards analysis were employed.

RESULTS

The comparative survival analysis of the entire group, based on overall survival (OS) and disease-free survival (DFS), revealed no significant difference between the pure and mixed groups (P = 0.480, HR = 1.474 [0.502-4.325] and P = 0.390, HR = 1.587 [0.550-4.640], respectively). However, in the pure IMPC group, certain factors were found to be associated with a higher risk of short survival. These factors included skin involvement (P = 0.050), pT3&4 category (P = 0.006), a ratio of intraductal component (> 5%) (P = 0.032), and high-level expression of N-cad (P = 0.020). Notably, none of the risk factors identified for short OS in pure IMPC cases were observed as significant risks in mixed cases and vice versa. Furthermore, N-cad was identified as a poor prognostic marker for OS in pure IMPCs (P = 0.002).

CONCLUSION

The selection of a 90% ratio for classifying pure IMPCs revealed significant differences in certain molecular and prognostic parameters between pure and mixed groups. Notably, the involvement of N-cadherin in the epithelial-mesenchymal transition (EMT) process provided crucial insights for predicting OS and DFS while also distinguishing between the two groups. These findings strongly support the notion that the pure IMPC subgroup represents a distinct entity characterized by unique molecular characteristics and behavioral patterns.

Comprehensive Immunohistochemical Analysis of Epithelial-Mesenchymal Transition Biomarkers in the Invasive Micropapillary Cancer of the Breast

Background: Invasive micropapillary carcinoma (IMPC) of the breast is commonly associated with a poor prognosis due to its high incidence of lymphovascular invasion and lymph node metastasis (LNM). Our study is aimed at investigating the prognostic significance of the expressions of E-cadherin (E-cad), N-cadherin (N-cad), CD44s, and β-catenin (β-cat). In addition, it is aimed at deciphering the consistency of these markers between the IMPC, the invasive breast carcinoma, no-special type (IBC-NST), and LNM components in the same IMPC cases. Methods: Sixty-two IMPC cases with LNM from 1996 to 2018 were analyzed. Immunohistochemical staining was performed separately on the three regions for each patient. Statistical analyses included Kaplan-Meier, Cox regression, and McNemar's statistical tests. Results: Loss of CD44 expression in IMPC, IBC-NST, and LNM areas was associated with poor prognosis in overall survival (OS) (p = 0.010, p < 0.0005, p = 0.025). Loss of CD44 expression in the IBC-NST, gain of N-cad expression in the IMPC, and loss of β-cat expression in the LNM areas were indicators of poor prognosis in disease-free survival (DFS) (p = 0.005, p = 0.041, p = 0.009). Conclusion: Our evaluation of this rare subtype, focusing on the expression of key epithelial-mesenchymal transition (EMT) molecules, revealed that it shares characteristics with the IBC-NST component within mixed tumors. Notably, contrary to expectations, a reduction in CD44 expression was found to adversely affect both OS and DFS. By conducting staining procedures simultaneously across three regions within the same patient, a novel approach has provided valuable insights into the mechanisms of EMT.

Chromophobe Renal Cell Carcinoma With Extensive Retraction Artifact: A Potential Diagnostic Pitfall From Micropapillary Urothelial Carcinoma

In addition to "classic" and eosinophilic subtype, chromophobe renal cell carcinoma (RCC) is well-known to demonstrate various morphological patterns including adenomatoid, microcystic, pigmented, multicystic, papillary, neuroendocrine-like, and small cell-like, all of which are important to appreciate for accurate diagnosis. Herein, we expand on a unique chromophobe RCC morphology not previously described consisting of tumor cells with extensive stromal retraction, mimicking upper urothelial tract micropapillary carcinoma (MPC). Twelve MPC-like chromophobe RCC nephrectomies were reviewed with clinicopathological features recorded; molecular testing was performed on 7 of 12 tumors. Patients were mostly men (n=10) with a mean age of 65 years. Mean tumor size was 6.4 cm with pathological stage distribution as follows: 4 (33%) T1a, 2 (17%) T1b, 1 (8%) T2b, and 3 (25%) T3a. The extent of MPC-like chromophobe RCC foci ranged from 10% to 40% (mean=26%; there was no correlation between the extent of MPC-like chromophobe RCC foci and tumor stage). Other chromophobe RCC morphological patterns were not identified. When performed, all (100%) tumors depicted prototypic chromophobe RCC staining pattern of KIT positivity/KRT7 positivity. Molecular showed 6 of 7 (86%) with multiple chromosomal losses. Clinically significant mutations were identified in NF1, TP53, FLCN (likely somatic), CHEK2, and ZFHX3 genes. Follow up available in 9 patients showed no evidence of disease (mean=23 months). Although the etiology behind the extensive stromal retraction in our tumors is unknown, this may likely be artifactual in nature. Nonetheless, it is important to include MPC-like chromophobe RCC in the spectrum of "variant" morphologies to avoid diagnostic pitfalls from micropapillary carcinoma.

Molecular Pathology of Micropapillary Carcinomas: Is Characteristic Morphology Related to Molecular Mechanisms?

Micropapillary carcinoma is an entity defined histologically in many organs. It is associated with lymph node metastasis and poor prognosis. The main mechanism for its histopathologic appearance is reverse polarization. Although the studies on this subject are limited, carcinomas with micropapillary morphology observed in different organs are examined by immunohistochemical and molecular methods. Differences are shown in these tumors compared with conventional carcinomas regarding the rate of somatic mutations, mRNA and miRNA expressions, and protein expression levels. TP53 , PIK3CA , TERT , KRAS , EGFR , MYC , FGFR1 , BRAF , AKT1 , HER2/ERBB2 , CCND1 , and APC mutations, which genes frequently detected in solid tumors, have also been detected in invasive micropapillary carcinoma (IMPC) in various organs. 6q chromosome loss, DNAH9 , FOXO3 , SEC. 63 , and FMN2 gene mutations associated with cell polarity or cell structure and skeleton have also been detected in IMPCs. Among the proteins that affect cell polarity, RAC1, placoglobin, as well as CLDNs, LIN7A, ZEB1, CLDN1, DLG1, CDH1 (E-cadherin), OCLN, AFDN/AF6, ZEB1, SNAI2, ITGA1 (integrin alpha 1), ITGB1 (integrin beta 1), RHOA, Jagged-1 (JAG1) mRNAs differentially express between IMPC and conventional carcinomas. Prediction of prognosis and targeted therapy may benefit from the understanding of molecular mechanisms of micropapillary morphology. This review describes the molecular pathologic mechanisms underlying the micropapillary changes of cancers in various organs in a cell polarity-related dimension.

Micropapillary Breast Carcinoma: From Molecular Pathogenesis to Prognosis

Invasive micropapillary carcinoma (IMPC) of the breast is an infrequent type of breast cancer often discussed for its potency for lymphovascular invasion and difficulty in accurate imaging estimation. Micropapillary carcinomas are noted to be present as larger tumors, of higher histological grade and a notably higher percentage of disease-positive lymph nodes. Hormonal and HER-2 positivity in IMPC is also commoner when compared to other NST carcinomas. IMPC occurs either as a pure form or more often as a component of mixed Non-Specific Type (NST) carcinoma. The latest data suggest that despite having comparable survival rates to other histological subtypes of breast carcinoma, effective surgical treatment often requires extended surgical margins and vigilant preoperative axillary staging due to an increased incidence of lymph node invasion, and locoregional recurrence. Moreover, the presence of micropapillary in situ components within tumors also seems to alter tumor aggression and influence the nodal disease stage. In this review, we present an overview of the current literature of micropapillary carcinoma of the breast from biology to prognosis, focusing on biological differences and treatment.