Annette Ramaswamy

Elevated expression of endoglin, a component of the TGF-β-receptor complex, correlates with proliferation of tumor endothelial cells

Endoglin/CD105 is a membrane protein involved in the TGF‐β receptor signalling pathway. Endoglin expression has been reported to be selective for a few cell types, in particular endothelial cells, although a number of conflicting reports have been published. In this study, we performed a detailed analysis of endoglin expression in human lung tumors and different tumor and endothelial cell lines, employing reverse‐transcriptase‐polymerase‐chain reaction as well as immunoblotting and immunohistochemistry using verified antibodies to endoglin. Our data show a clearly preferential expression of both endoglin mRNA and protein in endothelial cells. In tumors, endoglin expression was strongly elevated in the angiogenic endothelium at the tumor edges. In agreement with this observation, we find a clear correlation between endoglin expression and markers of proliferation, such as cyclin A and Ki‐67, suggesting that endoglin expression is linked to cell‐cycle regulation. These findings not only resolve some of the discrepancies in the literature, but also provide the basis for further applications making use of its selective localization and expression in the tumor vasculature. Int. J. Cancer 81:568–572, 1999.

Current concepts in the classification, diagnosis and treatment of hemangiomas and vascular malformations of the head and neck

Abstract There are many different classifications of vascular anomalies. As the correct classification of the vascular lesion has a direct influence on therapy it is difficult to decide which treatment should be considered as the treatment of choice. Based on an extensive review of the literature and personal experience of the treatment of more than 200 patients with hemangiomas or vascular malformations of the head and neck, a clinical classification is described that allows vascular lesions to be categorized in order to plan purposeful treatment. In general, hemangiomas represent the main group of vascular lesions in infancy and childhood. They are usually apparent a few weeks after birth and are characterized by an initially rapid growth of epithelial cells, followed by spontaneous involution. Hemangiomas should be differentiated from vascular malformations that are present at birth but may not be evident clinically. Spontaneous involution of vascular malformations has never been reported, whereas laser therapy can induce involution of hemangiomas at an early stage in a majority of cases. In certain situations steroids or surgical removal may seem to be the appropriate therapy of choice. In contrast, vascular malformations have to be treated according to their histopathology and location, as well as their hemodynamic features as shown radiographically with angiography. The accurate diagnosis of vascular anomalies is essential for further treatment, as shown by clinical experience at the University of Marburg.

Mutations of the DPC4/Smad4 gene in neuroendocrine pancreatic tumors

Tumors of the endocrine pancreas are extremely rare, and molecular mechanisms leading to their development are not well understood. A candidate tumor suppressor gene, DPC4, located at 18q21, has recently been shown to be inactivated in half of pancreatic adenocarcinoma xenografts. The close anatomical relationship of the exocrine and endocrine pancreas prompted us to determine the role of DPC4 in the tumorigenesis of 25 pancreatic islet cell tumors (11 insulinomas, nine non-functioning endocrine carcinomas, three gastrinomas, two vipomas). A mutation screening of the highly conserved COOH-terminal domain of DPC4 (exons 8 – 11) was performed by single-strand conformational variant (SSCP) analysis and a PCR-based deletion assay. Five of nine (55%) non-functioning endocrine pancreatic carcinomas revealed either point mutations, small intragenic deletions or homozygous deletion of DPC4 sequences compared to none of the insulinomas, gastrinomas or vipomas. These results suggest that DPC4 is an important target gene promoting tumorigenesis of non-functioning neuroendocrine pancreatic carcinomas.

CD34 + fibrocytes in invasive ductal carcinoma, ductal carcinoma in situ, and benign breast lesions

Abstract. The present study was undertaken in order to elucidate the question of whether the distribution of stromal CD34+ fibrocytes and smooth muscle actin (SMA)-reactive myofibroblasts differs between benign and malignant lesions of the breast. We investigated a total of 31 ductal carcinomas and 27 specimens with benign lesions of the breast (ductal hyperplasia, sclerosing adenosis, fibroadenoma, phyllodes tumor) and compared the distribution of CD34+ fibrocytes and SMA-reactive myofibroblasts. The stroma of normal breast tissue contained CD34+ fibrocytes, whereas SMA-reactive myofibroblasts were absent. All benign breast lesions exhibited stromal CD34+ fibrocytes and few lesions (fibroadenomas and phyllodes tumor) showed additional SMA-reactive myofibroblasts. In invasive breast cancer the stroma was devoid of CD34+ fibrocytes but a varying number of stromal SMA-reactive myofibroblasts was detectable. In the setting of the present study the loss of CD34+ fibrocytes was specific for invasive breast cancer and ductal carcinoma in situ, whereas SMA-reactive myofibroblasts were observed in different benign and malignant lesions. These findings may be helpful tools in distinguishing benign breast lesions (e.g., sclerosing adenosis) from invasive breast cancer and in characterizing stromal remodeling associated with invasive cancer.

CD34+ fibrocytes, α-smooth muscle antigen-positive myofibroblasts, and CD117 expression in the stroma of invasive squamous cell carcinomas of the oral cavity, pharynx, and larynx

We investigated tumor-free mucosa and squamous cell carcinomas of the oral cavity, the pharynx, and larynx with respect to the presence of stromal CD34+ fibrocytes and α-smooth muscle antigen (SMA)-positive myofibroblasts. Additionally, stromal expression of CD117 was analyzed. A total of 39 squamous cell carcinomas were assessed immunohistochemically. In all cases investigated, CD34+ fibrocytes were found in the tumor-free stroma, whereas α-SMA-positive myofibroblasts were lacking. Areas of lymphocytic infiltration disclosed a focal reduction of CD34+ fibrocytes. CD117 expression was absent from the tumor-free stroma. Of 39 squamous cell carcinomas, 33 were free of stromal CD34+ fibrocytes, and, in 31 carcinomas, stromal α-SMA-positive myofibroblasts occurred at least focally. CD117-positive stromal spindle cells were found in 25 carcinomas. Compared with tumor-free mucosa, the number of tissue mast cells was significantly increased in carcinomas. We conclude that stromal remodeling induced by invasive carcinomas is characterized by a loss of CD34+ fibrocytes and subsequent gain of α-SMA-positive myofibroblasts. The diagnostic impact of this finding is, however, limited by the fact that chronic inflammation may also be accompanied by a focal loss of CD34+ fibrocytes.

CD34+ fibrocytes in neoplastic and inflammatory pancreatic lesions.

Abstract. Besides its function as a matrix-producing cell, the CD34+ fibrocyte has been reported to be an antigen-presenting cell capable of priming naive T cells in situ. Therefore, it has been claimed that the CD34+ fibrocyte may play an important role in host response to tissue damage. The objective of the present study was to analyze the presence and distribution of CD34+ fibrocytes and smooth muscle actin (SMA) reactive myofibroblasts in relation to the underlying pancreatic disease. We investigated a total of 12 pancreatic adenocarcinomas, 7 endocrine tumors of the pancreas, and 8 cases of chronic pancreatitis; in 11 cases, normal pancreatic tissue was available. The stroma of normal pancreatic tissue harbored diffusely scattered CD34+ fibrocytes. Chronic pancreatitis was characterized by an increased number of stromal CD34+ fibrocytes paralleled by a gain of SMA reactive myofibroblasts which were not observed in the normal pancreatic stroma. The stroma of pancreatic ductal adenocarcinomas and endocrine tumors was devoid of CD34+ fibrocytes or showed at least a focal loss of this cell type, whereas SMA reactive myofibroblasts were detected in both endocrine tumors and adenocarcinomas. We conclude that detection of CD34+ fibrocytes may constitute an adjunctive tool in distinguishing chronic pancreatitis from ductal adenocarcinoma since the absence of this cell population strongly favors a neoplastic process. Moreover, CD34+ fibrocytes and myofibroblasts appear to be involved in stromal remodeling associated with chronic pancreatitis and ductal adenocarcinoma.

Sentinel node detection in N0 cancer of the pharynx and larynx.

Neck lymph node status is the most important factor for prognosis in head and neck squamous cell carcinoma. Sentinel node detection reliably predicts the lymph node status in melanoma and breast cancer patients. This study evaluates the predictive value of sentinel node detection in 50 patients suffering from pharyngeal and laryngeal carcinomas with a N0 neck as assessed by ultrasound imaging. Following 99m-Technetium nanocolloid injection in the perimeter of the tumour intraoperative sentinel node detection was performed during lymph node dissection. Postoperatively the histological results of the sentinel nodes were compared with the excised neck dissection specimen. Identification of sentinel nodes was successful in all 50 patients with a sensitivity of 89%. In eight cases the sentinel node showed nodal disease (pN1). In 41 patients the sentinel node was tumour negative reflecting the correct neck lymph node status (pN0). We observed one false-negative result. In this case the sentinel node was free of tumour, whereas a neighbouring lymph node contained a lymph node metastasis (pN1). Although we have shown, that skipping of nodal basins can occur, this technique still reliably identifies the sentinel nodes of patients with squamous cell carcinoma of the pharynx and larynx. Future studies must show, if sentinel node detection is suitable to limit the extent of lymph node dissection in clinically N0 necks of patients suffering from pharyngeal and laryngeal squamous cell carcinoma.

Analysis of β-Catenin Gene Mutations in Pancreatic Tumors

Background/Aim: Mutations of the adenomatous polyposis coli (APC) tumor suppressor gene have been described in a subset of pancreatic carcinomas. The APC gene modulates the β-catenin-Tcf pathway. The major player in this pathway is the β-catenin protein encoded by the β-catenin gene. A variety of different tumors, including colon, prostate, endometrial, and hepatocellular carcinomas, carry mutations in exon 3 of the β-catenin gene. The aim of this study was to determine the role of the β-catenin gene in the genesis of exocrine and endocrine tumors of the pancreas. Methods: 78 ductal pancreatic adenocarcinomas, 14 ductal pancreatic cancer cell lines, and 33 endocrine pancreatic tumors were evaluated for mutations in exon 3 of the β-catenin gene by single-strand conformation polymorphism analysis and direct DNA sequencing. In addition, 40 ductal pancreatic adenocarcinomas were analyzed for intracellular β-catenin accumulation by immunohistochemistry, indicating alterations of the β-catenin gene. Results: Neither the 111 exocrine and endocrine pancreatic tumors nor the 14 pancreatic cancer cell lines carried mutations in exon 3 of the β-catenin gene. Intracellular β-catenin accumulation was not identified in any of the 40 pancreatic adenocarcinomas. Conclusion: These data suggest that the β-catenin gene as the major player of the β-catenin-Tcf pathway does not play an important role in the genesis of pancreatic tumors.

p16INK4a is a Prognostic Marker in Resected Ductal Pancreatic Cancer: An Analysis of p16INK4a, p53, MDM2, an Rb

ObjectiveTo identify the prognostic relevance of the G1/S cell cycle regulator genes p16INK4a, p53, MDM2, and Rb in patients with resected ductal pancreatic cancer (PC). Summary Background DataThe tumor suppressor genes p16INK4a, p53, and Rb are altered in PC in 27% to 95%, 40% to 70%, and 5%, respectively. The role of MDM2 is not clearly defined in PC. The prognostic value of these cell cycle regulators has not been clarified. MethodsSixty-two patients with PC with complete follow-up who underwent potentially curative resections were included in the study. An extreme group analysis was performed including the 20 patients with the shortest survival and the 20 patients with the longest survival. Protein expression of p16, p53, MDM2, and Rb was investigated, and mutation analysis of p16INK4a and p53 was performed. p16INK4a promoter hypermethylation was examined by methylation-specific polymerase chain reaction. ResultsSignificantly more tumors in the shortest-surviving patients had p16INK4a alterations compared with tumors of the longest-surviving patients. In contrast, the frequency of p53 alterations was not significantly higher in the shortest-surviving versus the longest-surviving groups. Stabilization of MDM2 and loss of Rb expression were identified in a minority of tumors, independent of survival length. ConclusionsThe presence of p16INK4a alterations in resected tumors of patients with PC is connected with a worse prognosis, indicating patients that might benefit from adjuvant therapy regimens. p53 alterations, MDM2 overexpression, and loss of Rb expression could not be identified as prognostic markers from this study, but a larger study with greater statistical power might show a different result with regard to p53.

CD34+ fibrocytes in normal cervical stroma, cervical intraepithelial neoplasia III, and invasive squamous cell carcinoma of the cervix uteri

Abstract.CD34+ fibrocytes are widely distributed in normal connective tissues but have been reported to be absent within the stroma associated with invasive carcinomas. In the present study we investigated the presence and distribution of CD34+ fibrocytes and α-smooth muscle actin (α-SMA) positive myofibroblasts in cervical intraepithelial neoplasia III (CIN III; n=8), invasive carcinoma of the cervix (n=18) and adjacent normal cervical stroma. Normal cervical stroma and the stroma adjacent to CIN III disclosed a dense network of CD34+ fibrocytes, whereas the stroma of invasive carcinoma was virtually free of this cell population. Early stromal invasion by squamous carcinoma was characterized by a focal loss of CD34+ fibrocytes. α-SMA-positive myofibroblasts were not seen in the normal cervical stroma but occurred in six of eight cases of CIN III adjacent to the atypical epithelium. The stroma of invasive carcinoma was made up of large amounts of haphazardly arranged α-SMA-positive myofibroblasts. In the setting of the present study, a loss of CD34+ fibrocytes was specific for stromal alterations associated with invasive carcinoma and proved to be a sensitive tool in detecting small foci of stromal invasion. Therefore, detection of a loss of CD34+ fibrocytes may constitute an adjunctive tool in detecting (1) early stromal invasion and (2) invasive carcinoma in small biopsy specimens. Moreover, the present study shows that CD34+ fibrocytes and myofibroblasts play an important role in stromal remodeling associated with invasive squamous cell carcinoma of the cervix.