Immunocytochemical expression of E-cadherin on fine-needle aspirates from breast carcinomas correlate with the cell dissociation pattern seen on smears

E-cadherin clone 36 nuclear staining dictates adverse disease outcome in lobular breast cancer patients

Breast cancer is a heterogeneous disease and additional biomarkers for individually predicting patient outcomes are needed. Aberrant membrane E-cadherin immunoexpression has been demonstrated in lobular breast cancer. Also, E-cadherin nuclear staining has been reported, associating with prognosis in various tumors. Here, we explore whether membrane or nuclear staining of E-cadherin has the potential to dictate prognosis of patients with lobular breast cancer. We selected a cohort of 285 consecutively diagnosed lobular breast cancer patients and performed immunohistochemistry for E-cadherin (clones 36, EP700Y, and NCH38) and P-cadherin (clone 56C1) in representative formalin-fixed paraffin-embedded blocks. All patients were female, HER2-negative and surgically treated in a single institution. Survival curves were computed by Kaplan-Meier analysis. Hazard ratios and respective 95% confidence intervals were estimated using Cox regression models. Statistical significance was set at p < 0.05. Nuclear staining for E-cadherin clone 36 was frequent (35%), contrarily to other antibodies tested. Negative correlation was found between nuclear and membrane E-cadherin clone 36 immunostaining (r_s = -0.30, p < 0.001), whereas positive correlation was found between membrane immunoexpression of E-cadherin clone 36 and P-cadherin (r_s = 0.31, p < 0.001). Patients with any evidence of E-cadherin clone 36 nuclear immunostaining disclosed significantly worse overall survival, disease-specific-survival and disease/progression-free survival (hazard ratio = 2.059, 95% confidence interval 1.313-3.230; hazard ratio = 1.980, 95% confidence interval 1.121-3.495; and hazard ratio = 2.341, 95% confidence interval 1.403-3.905, respectively). Differences in survival were more remarkable when considering nuclear E-cadherin immunoexpression in ≥50% tumor cells. Poorer survival was maintained in multivariable analysis, after adjusting for age, menopausal and PR status, treatment course, vascular invasion, tumor grade and stage. Our results support the use of antibodies against the cytoplasmic domain of E-cadherin, such as clone 36, which may reveal nuclear immunostaining and indicate more aggressive clinical course in patients with lobular breast cancer. We hypothesize that E-cadherin is cleaved and translocated to nucleus functioning as transcription factor.

Association between Breast Cancer Recurrence and Cellular Dissociation Assessed Using Fine-Needle Aspiration

OBJECTIVE

To determine the associations between breast cancer recurrence and cytological findings of fine-needle aspiration cytology (FNAC).

STUDY DESIGN

The study included 117 women who had undergone a modified radical mastectomy for invasive ductal carcinoma of the breast. FNAC samples of these patients were reexamined, and cytological findings, such as cellular dissociation, nuclear pleomorphism, nuclear atypia, chromatin pattern, and nuclear size, were scored. Uni- and multivariate analyses were performed to determine the prognostic significance of the cytological findings. Corresponding cancer tissues were immunostained for estrogen receptor, progesterone receptor, human epidermal growth factor 2 (HER2), p53, and E-cadherin to determine their associations with cytological findings. Coexpression of Arp2 and WAVE2 was also examined immunohistochemically as a cell locomotion signal.

RESULTS

Cellular dissociation (p = 0.0259) and nuclear size (p = 0.0417) were significantly associated with cancer recurrence. Multivariate analysis showed that cellular dissociation and histological grade were significant independent predictors of cancer recurrence. Cellular dissociation was found to be associated with coexpression of Arp2 and WAVE2 (p = 0.0356) and HER2 (p = 0.0469).

CONCLUSION

The cytological finding of cell dissociation was associated with the activation of Arp2 and WAVE2 signals and was an independent predictor of recurrence.

Disseminated breast cancer cells acquire a highly malignant and aggressive metastatic phenotype during metastatic latency in the bone

Background

Disseminated tumor cells (DTCs) in the bone marrow may exist in a dormant state for extended periods of time, maintaining the ability to proliferate upon activation, engraft at new sites, and form detectable metastases. However, understanding of the behavior and biology of dormant breast cancer cells in the bone marrow niche remains limited, as well as their potential involvement in tumor recurrence and metastasis. Therefore, the purpose of this study was to investigate the tumorigenicity and metastatic potential of dormant disseminated breast cancer cells (prior to activation) in the bone marrow.

Methodology/Principal Findings

Total bone marrow, isolated from mice previously injected with tumorspheres into the mammary fat pad, was injected into the mammary fat pad of NUDE mice. As a negative control, bone marrow isolated from non-injected mice was injected into the mammary fat pad of NUDE mice. The resultant tumors were analyzed by immunohistochemistry for expression of epithelial and mesenchymal markers. Mouse lungs, livers, and kidneys were analyzed by H+E staining to detect metastases. The injection of bone marrow isolated from mice previously injected with tumorspheres into the mammary fat pad, resulted in large tumor formation in the mammary fat pad 2 months post-injection. However, the injection of bone marrow isolated from non-injected mice did not result in tumor formation in the mammary fat pad. The DTC-derived tumors exhibited accelerated development of metastatic lesions within the lung, liver and kidney. The resultant tumors and the majority of metastatic lesions within the lung and liver exhibited a mesenchymal-like phenotype.

Conclusions/Significance

Dormant DTCs within the bone marrow are highly malignant upon injection into the mammary fat pad, with the accelerated development of metastatic lesions within the lung, liver and kidney. These results suggest the acquisition of a more aggressive phenotype of DTCs during metastatic latency within the bone marrow microenvironment.

Cellular cohesion as a prognostic factor in malignant melanoma: a retrospective study with up to 12 years follow-up

Malignant melanomas have a high metastatic potential. Although the depth of tumour invasion is the single most important histological prognostic factor, in clinical practice this correlation is frequently challenged. In this study, we assessed the cohesion of malignant melanocytes in the dermal component of all primary melanomas in vertical growth phase with tumour thickness >0.76 mm diagnosed in our Department between 1990 and 1995. The rationale behind this morphological evaluation was based on the hypothesis that a change in the adhesion molecule profile of melanoma cells may manifest visually discrete changes in the way that cells group together in dermal aggregates. We used a dyscohesion score based on the proportion of invasive tumour occupied by dyscohesive neoplastic cells and assessed its clinical significance by correlating it with the incidence of recurrence, regional and distant metastases and survival of the patients. Follow-up was up to 12 years. We found that the degree of melanoma cell dyscohesion was associated with the probability of local recurrence or metastasis. This correlation was particularly significant when dyscohesion involving an area smaller than 25% (dyscohesion score 1) of the dermal component was compared to dyscohesion involving a larger area (scores 2-4). Melanomas in the latter group had significantly increased likelihood of recurrence or metastasis (P<0.025, log-rank test). This was particularly the case in T1-T3 melanomas (P<0.005). Similarly, T1-T3 melanomas with dyscohesion score 1 had a significantly higher survival rate (P<0.025). In the same cohort, both disease-free survival and survival were not significantly correlated to thickness, probably due to the limited number of cases. Finally, we showed that extent of dyscohesion was independent of Breslow thickness or tumour regression. We believe that estimation of melanoma cell dyscohesion is a reliable histological prognostic factor that may be appropriate in clinical practice.

Restoration of E-cadherin cell-cell junctions requires both expression of E-cadherin and suppression of ERK MAP kinase activation in Ras-transformed breast epithelial cells

E-cadherin is a main component of the cell-cell adhesion junctions that play a principal role in maintaining normal breast epithelial cell morphology. Breast and other cancers that have up-regulated activity of Ras are often found to have down-regulated or mislocalized E-cadherin expression. Disruption of E-cadherin junctions and consequent gain of cell motility contribute to the process known as epithelial-to-mesenchymal transition (EMT). Enforced expression of E-cadherin or inhibition of Ras-signal transduction pathway has been shown to be effective in causing reversion of EMT in several oncogene-transformed and cancer-derived cell lines. In this study, we investigated MCF10A human breast epithelial cells and derivatives that were transformed with either activated H-Ras or N-Ras to test for the reversion of EMT by inhibition of Ras-driven signaling pathways. Our results demonstrated that inhibition of mitogen-activated protein kinase (MAPK) kinase, but not PI3-kinase, Rac, or myosin light chain kinase, was able to completely restore E-cadherin cell-cell junctions and epithelial morphology in cell lines with moderate H-Ras expression. In MCF10A cells transformed by a high-level expression of activated H-Ras or N-Ras, restoration of E-cadherin junction required both the enforced reexpression of E-cadherin and suppression of MAPK kinase. Enforced expression of E-cadherin alone did not induce reversion from the mesenchymal phenotype. Our results suggest that Ras transformation has at least two independent actions to disrupt E-cadherin junctions, with effects to cause both mislocalization of E-cadherin away from the cell surface and profound decrease in the expression of E-cadherin.

Reduced expression of Claudin-7 in fine needle aspirates from breast carcinomas correlate with grading and metastatic disease

OBJECTIVE

To study the immunocytochemical expression of the tight junction protein Claudin-7 in smears from breast carcinomas and correlate with grading, nodal status, locoregional and distant metastases and the cellular cohesion.

METHODS

The material consisted of 52 air-dried smears from fine needle aspirates of breast carcinomas, both primary and metastatic and smears from seven benign lesions. A primary antibody to Claudin-7 was used for immunocytochemical staining. The degree of staining was recorded as negative, reduced or full, with full expression meaning equivalent to the staining pattern found in the fibroadenomas used as benign control. Staining intensity and the percentage of stained cells were evaluated. The control smears revealed a strong membrane and cytoplasmic positivity in all luminal epithelial cells. Cellular cohesion was graded as: (1) mainly cohesive groups, (2) groups and single cells and (3) mainly single cells.

RESULTS

All primary and recurrent/metastatic breast lesions expressed Claudin-7. Full expression was demonstrated in 46% of the cases. Reduced expression was found in 54%. In cases with reduced expression, the percentage of stained cells were usually high, and no smear showed <50% stained tumour cells. The staining pattern was heterogeneous and always mixed membrane/cytoplasmic. Claudin-7 expression showed a significant correlation (P < 0.05) with grading, locoregional and distant metastases, nodal involvement and cellular cohesion in invasive carcinomas, but not with tumour size or subtype.

CONCLUSION

Reduced expression of Claudin-7 correlated with higher tumour grade, metastatic disease, including loco-regional recurrences and with cellular discohesion.

Variable E-cadherin expression in a MNU-induced colon tumor model in rats which exposed with 50 Hz frequency sinusoidal magnetic field

Inactivation of the E-cadherin system by multiple mechanisms, including both genetic and epigenetic events, plays a significant role in multistage carcinogenesis. We have investigated the effects of sinusoidal electromagnetic fields (SMF) on E-cadherin expression in an MNU (N-methyl-N-nitrosurea)-induced colon tumor model. Male wistar albino rats were used for the study. The rats were classified into four groups: I (MNU), II (SMF+MNU), III (SMF) and IV (control). After administered at MNU in 1st and 2nd groups, 2nd and 3rd groups were exposed to a sinusoidal magnetic field (SMF, 50 Hz, 5 mT) for 6 hours/day for 8 months. The expression of E-cadherin were examined in four groups of rat colon tissues by immunohistochemistry on paraffin sections. For immunohistochemical analysis, the labeled streptavidin biotin method was performed using a Vectastain Universal Quick Kit with microwave accentuation. Fisher's exact test was used for statistical analysis between proportions. Immunohistochemical studies of E-cadherin expression in this model demonstrated significant differences for cytoplasmic expression pattern. These results suggest that the electromagnetic fields result in significant alterations in cell adhesion mechanisms. This study has implications for understanding the role of fields in cell detachment in cancer metastasis. Further work is required to determine the relative effect of the magnetic fields on these phenomena.