Geza Acs

Differential Expression of E-Cadherin in Lobular and Ductal Neoplasms of the Breast and Its Biologic and Diagnostic Implications

We studied the pattern of E-cadherin expression in 183 invasive carcinomas (100 ductal, 42 lobular, 41 with mixed ductal and lobular features) and 198 in situ carcinomas (131 ductal, 53 lobular, 14 in situ with ductal and lobular features) by immunohistochemistry. We found a highly significant correlation of E-cadherin membrane expression with the histologic phenotype of the tumors. While moderate to strong membrane expression of E-cadherin was seen in all invasive and in situ ductal carcinomas, 41 of 42 invasive and 50 of 53 in situ lobular carcinomas showed complete loss of expression. All in situ carcinomas diagnosed histologically as showing mixed ductal and lobular features demonstrated complete loss of staining. Invasive carcinomas with ductal and lobular features showed 3 staining patterns: (1) complete or almost complete lack of membrane staining similar to that seen in lobular carcinomas, (2) uniform membrane expression throughout the tumor similar to ductal carcinomas, and (3) focal loss of E-cadherin staining, which correlated well with the histologic impression of focal lobular features. In tumors with histologically equivocal features, immunohistochemical detection of E-cadherin expression can be a useful diagnostic tool for the differentiation of ductal and lobular carcinomas of the breast.

Utility of D2-40, a novel mesothelial marker, in the diagnosis of malignant mesothelioma

Although immunohistochemistry has proven to be valuable in the differentiation of epithelioid mesothelioma from pulmonary or metastatic adenocarcinoma, no single antibody has demonstrated absolute sensitivity or specificity in making this distinction. Using immunohistochemical analysis with D2-40, a recently available monoclonal antibody that has been used as a lymphatic endothelial marker, we examined 53 cases of mesothelioma, 28 cases of reactive pleura, 30 cases of pulmonary adenocarcinoma, 35 cases of renal cell carcinoma, 26 cases of ovarian serous carcinoma, 16 cases of invasive breast carcinoma, 11 cases of prostatic adenocarcinoma, and seven cases of urothelial carcinoma. In addition, immunohistochemistry using calretinin, cytokeratin 5/6, and WT1 was performed on all cases of mesothelioma, pulmonary adenocarcinoma, ovarian serous carcinoma, and renal cell carcinoma. Predominantly, membranous D2-40 immunoreactivity was present in 51 of 53 (96%) mesotheliomas, 27 of 28 (96%) cases of reactive pleura, and 17 of 26 (65%) ovarian serous carcinomas; membranous staining was not seen in any other tumors examined. Compared to other immunohistochemical markers of mesothelioma, D2-40 was as sensitive as calretinin and more sensitive than cytokeratin 5/6 and WT1. We conclude that D2-40 immunoreactivity is sensitive for cells of mesothelial origin, and may be useful in the differential diagnosis of epithelioid malignant mesothelioma vs adenocarcinoma.

Renal carcinomas with the t(6;11)(p21;q12): Clinicopathologic features and demonstration of the specific alpha-TFEB gene fusion by immunohistochemistry, RT-PCR, and DNA PCR

A highly distinctive subset of renal neoplasms of children and young adults contains a t(6;11)(p21;q12), a translocation recently been shown to result in fusion of Alpha, a gene on 11q12, with the transcription factor gene TFEB on 6p21. To define the clinicopathologic spectrum of this nascent entity and to establish immunohistochemical (IHC) and molecular methods for the detection of the specific Alpha-TFEB fusion, we studied 7 renal neoplasms that showed the t(6;11) by cytogenetic or molecular analysis (patient age: range, 9-33 years; mean, 17 years). While all tumors were confined to the kidney, 3 tumors demonstrated vascular invasion. In limited follow-up, none has metastasized. We postulated that the Alpha-TFEB gene fusion may result in deregulated expression of TFEB protein that would be detectable by IHC. Using a polyclonal antibody to TFEB on formalin-fixed, paraffin-embedded tissue sections, we found that all 7 renal neoplasms with the t(6;11) demonstrated moderate (2 cases) or strong (5 cases) nuclear TFEB immunoreactivity. In contrast, none of 1089 other tumors (of 74 histologic types from 16 sites) labeled significantly for TFEB. Nuclear immunoreactivity for TFEB in normal tissues was extremely rare, limited to weak labeling of scattered benign lymphocytes. We also show that the Alpha-TFEB fusion RNAs are highly variable in size and structure, making detection by reverse-transcriptase polymerase chain reaction (RT-PCR) less reliable than for other gene fusions. Because Alpha is an intronless gene and therefore lacks splice signals, we hypothesized that DNA PCR and RT-PCR products would be identical, allowing for the use of more robust molecular assays based on genomic DNA. Indeed, in 2 cases with available frozen tissue, we showed the genomic Alpha-TFEB junction detected by DNA PCR to be identical to the Alpha-TFEB fusion mRNA detected by RT-PCR. In summary, renal neoplasms with the t(6;11) are a distinctive neoplastic entity with many similarities to the Xp11 translocation carcinomas, and together with the latter form a growing “MiTF/TFE family” of translocation carcinomas. Nuclear immunoreactivity for TFEB protein is a highly sensitive and specific diagnostic marker for these renal neoplasms. Finally, the special molecular features of the Alpha-TFEB gene fusion allow its molecular detection by DNA PCR as a robust alternative to RT-PCR in clinical tumor samples.

Hypoxia-Inducible Erythropoietin Signaling in Squamous Dysplasia and Squamous Cell Carcinoma of the Uterine Cervix and Its Potential Role in Cervical Carcinogenesis and Tumor Progression

Tissue hypoxia is a characteristic property of cervical cancers that makes tumors resistant to chemo- and radiation therapy. Erythropoietin (Epo) is a hypoxia-inducible stimulator of erythropoiesis. Acting via its receptor (EpoR), Epo up-regulates bcl-2 and inhibits apoptosis of erythroid cells and rescues neurons from hypoxic damage. In addition to human papillomavirus infection, increased bcl-2 expression and decreased apoptosis are thought to play a role in the progression of cervical neoplasia. Using reverse transcriptase-polymerase chain reaction and Western blotting we showed that HeLa and SiHa cervical carcinoma cells and human cervical carcinomas express EpoR, and that hypoxia enhances EpoR expression. Exogenous Epo stimulated tyrosine phosphorylation and inhibited the cytotoxic effect of cisplatin in HeLa cervical carcinoma cells. Using immunohistochemistry, we examined the expression of Epo, EpoR, p16, hypoxia-inducible factor (HIF)-1alpha, and bcl-2 in benign and dysplastic cervical squamous epithelia and invasive squamous cell carcinomas (ISCCs). EpoR expression in benign epithelia was confined to the basal cell layers, whereas in dysplasias it increasingly appeared in more superficial cell layers and showed a significant correlation with severity of dysplasia. Diffuse EpoR expression was found in all ISCCs. Expression of Epo and HIF-1alpha was increased in dysplasias compared to benign epithelia. Focal Epo and HIF-1alpha expression was seen near necrotic areas in ISCCs, and showed correlation in their spatial distribution. Significant correlation was found between expression of EpoR, and p16 and bcl-2 in benign and dysplastic squamous epithelia. Our results suggest that increased expression of Epo and EpoR may play a significant role in cervical carcinogenesis and tumor progression. Hypoxia-inducible Epo signaling may play a significant role in the aggressive behavior and treatment resistance of hypoxic cervical cancers.

Peritumoral Lymphatic Vessel Density and Vascular Endothelial Growth Factor C Expression in Early-Stage Squamous Cell Carcinoma of the Uterine Cervix

Purpose: Lymphatic invasion and nodal metastasis plays a major role in the spread of cervical cancer; however, little is known about the mechanisms whereby tumor cells enter the lymphatic system. Experimental Design: We examined the intra- and peritumoral lymphatic vessel density (LVD) using D2-40 immunohistochemistry in 111 cervical squamous cell carcinomas and correlated them with vascular endothelial growth factor (VEGF)-C expression, clinicopathologic tumor features, and outcome. Results: Compared with benign cervix, intratumoral and peritumoral LVD was significantly increased (P < 0.0001). Peritumoral LVD was significantly higher than intratumoral LVD (P = 0.009). High peritumoral, but not intratumoral, LVD showed significant correlation with high tumor stage, lymphatic invasion, and nodal metastasis. VEGF-C showed increased expression at the invasive edge compared with the center of tumors (P < 0.0001) and correlated with high peritumoral LVD, lymphatic invasion, and nodal metastasis. High peritumoral LVD and VEGF-C expression at the invasive edge of tumors were associated with poor overall and recurrence-free survival in univariate analysis. In multivariate analysis, peritumoral LVD was the only independent term predictive of overall survival. Conclusions: Our findings suggest a potential role for VEGF-C in tumor-induced lymphangiogenesis represented by high peritumoral LVD, which may be one of the mechanisms leading to lymphatic invasion and metastatic spread. High peritumoral LVD may be an independent prognostic factor in early-stage cervical cancer.

Immunohistochemical expression of erythropoietin and erythropoietin receptor in breast carcinoma

Erythropoietin (Epo), induced by hypoxia, controls the survival, proliferation, and differentiation of Epo receptor (EpoR)‐bearing erythroid progenitors and plays a role in the protection of neurons from hypoxic damage. Hypoxia in malignant disease is associated with invasion, metastasis, resistance to therapy, and selection for cells with diminished apoptotic potential. The authors recently demonstrated the basal and hypoxia‐stimulated expression of Epo and EpoR in human breast carcinoma cell lines and in breast carcinomas, suggesting a role for autocrine Epo signaling in the hypoxic adaptations of mammary neoplasms.

WT1 is differentially expressed in serous, endometrioid, clear cell, and mucinous carcinomas of the peritoneum, fallopian tube, ovary, and endometrium

Summary:The Wilms’ tumor gene WT1 plays complex roles in the development of the organs of the genitourinary tract and mesothelium, as well as Wilms’ tumors. Although its biologic role is still unclear, most serous carcinomas of the ovary and peritoneum, mesotheliomas, and Wilms’ tumor have been shown to express WT1. A recent study, however, found no WT1 expression in serous carcinomas of the endometrium, suggesting that WT1 could be useful in identifying the primary site of serous carcinomas. We examined the expression of WT1 and p53 by immunohistochemistry in 69 cases of endometrial carcinoma (35 endometrioid, 18 clear cell, 16 serous), 68 cases of ovarian carcinoma (28 serous, 11 endometrioid, 18 clear cell, and 11 mucinous), 14 fallopian tube carcinomas (12 serous, 2 endometrioid), and 20 primary peritoneal serous carcinomas. WT1 nuclear reactivity of any extent and intensity was considered positive. Immunohistochemical stains were evaluated semiquantitatively using a four-tiered scale. Among endometrial carcinomas, WT1 immunoreactivity was seen in 10 of 16 serous, but in none of 35 endometrioid or 18 clear cell carcinomas. Among ovarian tumors, WT1 expression was seen in 24 of 28 serous and 4 of 18 clear cell carcinomas, but in none of 11 endometrioid and 11 mucinous tumors. All 12 serous carcinomas but none of 2 endometrioid carcinomas of the fallopian tube were positive for WT1. WT1 expression was seen in 19 of 20 serous primary peritoneal carcinomas. The difference in WT1 expression was highly significant between serous and other types of tumors in all sites (p<0.0001, chi-square test), although the level of WT1 expression was significantly different among serous carcinomas arising at different sites (p<0.0001, Kruskal-Wallis test). A significant positive correlation was found between the level of p53 and WT1 expression in all carcinomas combined (r = 0.3935, p<0.0001, Spearman test), but when only serous carcinomas were analyzed, the correlation between p53 and WT1 expression levels did not reach statistical significance. Our results suggest that WT1 expression in epithelial tumors of the female genital tract may be related to cell differentiation and histologic subtypes of carcinomas, rather than to primary site of origin.

Mutant V600E BRAF Increases Hypoxia Inducible Factor-1α Expression in Melanoma

Mutations in the BRAF serine/threonine kinase gene are frequently found in cutaneous melanomas. Activation of hypoxia inducible factor-1alpha (HIF-1alpha) in response to both hypoxic stress and oncogenic signals has important implications in cancer development and progression. Here, we report that mutant BRAF(V600E) increases HIF-1alpha expression in melanoma cells. Our microarray profiling data in 35 melanoma and melanocyte cell lines showed that HIF-1alpha gene expression was significantly increased in melanomas harboring BRAF(V600E) mutation. Stable suppression of mutant BRAF(V600E) or both wild-type and mutant BRAF(V600E) by RNA interference in melanoma cells resulted in significantly decreased HIF-1alpha expression. Knockdown of mutant BRAF(V600E) induced significant reduction of cell survival and proliferation under hypoxic conditions, whereas knockdown of both wild-type and mutant BRAF(V600E) resulted in further reduction. The effects of BRAF knockdown can be rescued by reintroducing BRAF(V600E) into tumor cells. Transfection of BRAF(V600E) into melanoma cells with wild-type BRAF induced significantly more hypoxic tolerance. Knockdown of HIF-1alpha in melanoma cells resulted in decreased cell survival under hypoxic conditions. Pharmacologic inhibition of BRAF by BAY 43-9006 also resulted in decreased HIF-1alpha expression. Although HIF-1alpha translational rate was not changed, the protein was less stable in BRAF knockdown cells. In additional, von Hippel-Lindau protein expression was significantly increased in BRAF knockdown cells. Our data show for the first time that BRAF(V600E) mutation increases HIF-1alpha expression and melanoma cell survival under hypoxic conditions and suggest that effects of the oncogenic V600E BRAF mutation may be partially mediated through the HIF-1alpha pathway.

Prognostic significance of erythropoietin expression in human endometrial carcinoma.

Erythropoietin (Epo), which is induced by hypoxia, controls erythropoiesis and protects neurons from hypoxic damage. Hypoxia in malignant disease is associated with invasion, metastasis, and resistance to therapy. The authors recently demonstrated hypoxia‐stimulated expression of Epo and Epo receptor (EpoR) in human breast and cervical carcinomas, suggesting a role for autocrine Epo signaling in the hypoxic adaptations of carcinomas.

Low D2-40 immunoreactivity correlates with lymphatic invasion and nodal metastasis in early-stage squamous cell carcinoma of the uterine cervix

Lymphatic invasion and nodal metastasis are predictors of shorter disease-free and overall survival in carcinoma of the uterine cervix. The monoclonal antibody D2-40, which reacts with the oncofetal membrane antigen M2A, is a new selective marker for lymphatic endothelium, and has been shown to be useful in identifying the presence of lymphatic invasion in various malignant neoplasms, including cervical carcinoma. However, the reactivity of the tumor cells with D2-40 has not yet been evaluated. In this study, we examined the pattern of D2-40 immunoreactivity in a series of 138 invasive squamous cell carcinomas of the uterine cervix. We correlated the presence and extent of D2-40 immunoreactivity in the tumor cells with various clinicopathologic features, the presence of lymphatic invasion, lymph node metastasis and outcome. Diffuse or focal D2-40 immunoreactivity was present in 17 (12%) and 81 (59%) tumors, respectively, while 40 (29%) tumors showed no immunoreactivity. Lymphatic invasion and nodal metastasis were present in 56 and 29% of tumors, respectively. Tumor emboli within lymphatic spaces and metastatic tumor foci in lymph nodes showed no immunoreactivity in 86 and 80% of the cases, respectively. Lymphatic invasion and nodal metastasis were significantly more common in tumors showing low D2-40 immunoreactivity (P<0.0001 and 0.022, respectively). D2-40 immunoreactivity showed no correlation with any other clinicopathologic features examined, including tumor size, grade and FIGO stage. In univariate analysis low D2-40 immunoreactivity was significantly associated with shorter recurrence-free, but not with overall survival. Our studies suggest that D2-40 immunostaining may serve as a marker for increased risk of lymphatic invasion and tumor recurrence in cervical biopsy material. Further study of the biological function of the M2A antigen may shed some light on the interaction of tumor cells with lymphatics.