Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Richard W. Brown is active.

Publication


Featured researches published by Richard W. Brown.


Cancer | 1997

Overexpression of Glut1 and Glut3 in stage I nonsmall cell lung carcinoma is associated with poor survival.

Mamoun Younes; Richard W. Brown; Mark Stephenson; Margaret Gondo; Philip T. Cagle

Increased expression of Glut1 and Glut3 has been reported in many human cancers, including nonsmall cell lung carcinoma (NSCLC). The aim of this study was to determine the biologic significance of Glut1 and Glut3 overexpression in Stage I NSCLC.


Human Pathology | 1993

Multiple-marker immunohistochemical phenotypes distinguishing malignant pleural mesothelioma from pulmonary adenocarcinoma.

Richard W. Brown; Gary M. Clark; Atul K. Tandon; D. Craig Allred

The diagnostic distinction between malignant pleural epithelial mesothelioma and pulmonary adenocarcinoma is often difficult and partially reliant on the use of immunohistochemistry (IHC). While there are several available IHC markers preferentially expressed in adenocarcinomas compared with mesotheliomas, there are no readily available or well-validated markers preferentially expressed in mesotheliomas and no markers are absolutely specific for either tumor. Thus, there always will be an element of doubt regarding the identity of lesions diagnosed by IHC using these markers and an undesirable reliance on negative results if the lesion is truly a mesothelioma. To help optimize the ability of currently available but imperfect markers to resolve adenocarcinoma and mesothelioma and to minimize the impact of false-negative results on their diagnosis, a systematic study was undertaken to identify multiple-marker immunostaining phenotypes that are the most specific and sensitive for each type of tumor. The study involved staining a series of malignant epithelial mesotheliomas (n = 34) and pulmonary adenocarcinomas (n = 103) with eight markers that were selected on the basis of previous reports of their relatively restricted specificities for one or the other of these lesions (and included carcinoembryonic antigen [CEA], tumor-associated glycoprotein 72 [B72.3], Leu-M1, vimentin, thrombomodulin, secretory component, carcinoma antigen-125, and periodic-acid-Schiff with diastase [for mucin]. Considering the markers one, two, and three at a time, all possible combinations of results were analyzed by computer to identify the phenotype most sensitive and specific for adenocarcinoma or mesothelioma. The best single marker was CEA (positive: 97% specific and sensitive for adenocarcinoma; negative: 97% specific and sensitive for mesothelioma). However, because examples of both tumor types expressed CEA, none of the study cases were unequivocally resolved and the risk of false-negative results was relatively high. The best two markers were CEA and B72.3 (both positive: 100% specific and 88% sensitive for adenocarcinoma; both negative: 99% specific and 97% sensitive for mesothelioma). The four possible combinations of results for these two markers resolved 68% of cases (93 of 137 cases), with less risk of false-negative results than a single marker. In general, several three-marker panels resulted in sensitivities and specificities similar to the two-marker panel of CEA and B72.3. In particular, the three-marker panel of CEA, B72.3, and Leu-M1 resulted in eight possible phenotypes that resolved 74% of cases (101 of 137 cases), with even further reduced risk of false-negative results.(ABSTRACT TRUNCATED AT 400 WORDS)


The American Journal of Surgical Pathology | 1998

Adult mesoblastic nephroma: expansion of the morphologic spectrum and review of literature.

Luan D. Truong; Russel H. Williams; Thu Ngo; Charles Cawood; Patricia Chevez-Barrios; Hazel L. Awalt; Richard W. Brown; Mamoun Younes; Jae Y. Ro

Mesoblastic nephroma (MN) is a distinctive tumor that is seen mostly in early infancy and that consists of classic and cellular (atypical) variants. Mesoblastic nephroma rarely occurs in adulthood, but MN in this age group still is poorly characterized because there are only 17 reported cases. We describe five additional cases of adult MN, including one case of the cellular variant, characterize the immunohistochemical profiles in detail, and critically review the previously reported cases. The collective data obtained from these 22 cases of adult MN showed that the patients predominantly were women (20 cases), ranging in age from 19 to 78 years, who were asymptomatic (5 cases) or had nonspecific signs and symptoms referable to a renal mass. Twenty tumors were classified as classic and 2 as cellular. The tumors were 2-24 cm, well circumscribed, and partially encapsulated and displayed a solid/ cystic cut surface, with a predominantly solid component in most tumors. One tumor, however, was almost purely cystic. Most tumors extended to the renal sinus. and some appeared entirely intrapelvic on imaging studies; however, gross and microscopic evaluation did not show destructive invasion of the pelvic wall. Extension of the tumor beyond the renal capsule has not been described. Each tumor was composed of epithelial and stromal components both. The epithelial component, which displayed no difference between the classic and cellular variants, was composed of isolated or clustered tubules and cysts lined by a benign epithelium with a wide range of cytologic differentiation. The stromal cells were composed of fibroblasts, myofibroblasts, and smooth muscle cells in various combinations. Stromal cellularity was low for the classic variant but high for the cellular variant. Hemorrhage, necrosis, and high mitotic index were noted in the stroma of the cellular, but not in the classic variant. Immunohistochemical study applied to the five current cases and seven normal control kidneys confirmed the presence of fibroblasts, myofibroblasts, smooth muscle cells, and prominent vessels in the stroma of each tumor. Most cysts and tubules within the tumors had a distinctive immunohistochemical profile, similar to that of collecting duct but different from those of other portions of the nephron in the normal control kidneys. After total or partial nephrectomy, without adjuvant chemotherapy or radiotherapy, 19 patients, including the 2 with cellular MN, were alive and well at 8-months to 48-years follow-up. Follow-up was not available in two patients. The remaining patient had recurrence at the surgical site 24 years after nephrectomy. Adult MN displays a distinctive morphologic spectrum that parallels that of its pediatric congener. It probably is a benign tumor that can be treated successfully by complete excision. The collecting duct differentiation expressed by most tubules and cysts of adult MN implies ureteric bud, which is the exclusive embryologic origin of collecting duct, as an important element in the histogenesis of this rare but fascinating type of tumor.


Human Pathology | 1994

p53 immunostaining in the differentiation of reactive processes from malignancy in pleural biopsy specimens

Philip T. Cagle; Richard W. Brown; Russell M. Lebovitz

To determine the utility of positive p53 protein immunostaining as an adjunct in the diagnosis of malignancy in pleural biopsy specimens, we reviewed 73 recently obtained pleural biopsy specimens that represented the typical range of diagnoses encountered in the evaluation of a proliferative pleural process. Immunohistochemistry was performed on paraffin sections of each biopsy specimen using a monoclonal antibody to the p53 suppressor gene product clone BP53-12 (BioGenex, San Ramon, CA) and a standard capillary gap (Microprobe, Fischer Scientific, Pittsburgh, PA) avidin-biotin complex technique with a citrate buffer antigen retrieval solution. Of the pleural biopsy specimens with unequivocal malignancy, 19 of 40 mesotheliomas and nine of 18 metastatic adenocarcinomas were immunopositive for p53 protein. All 13 of the biopsy specimens with reactive mesothelial hyperplasia or organizing pleuritis were negative. Two pleural biopsy specimens, which were interpreted as suspicious but inconclusive for malignancy, were positive for p53 protein and subsequent pathology specimens confirmed the presence of metastatic carcinoma in both of these biopsy specimens. Our findings suggest that p53 protein immunostaining is relatively sensitive and highly specific in differentiating reactive processes from primary or metastatic malignancies in histopathologically equivocal pleural biopsy specimens.


Human Pathology | 1997

Absence of prognostic significance of bcl-2 immunopositivity in non-small cell lung cancer: Analysis of 427 cases

Rose C. Anton; Richard W. Brown; Mamoun Younes; Margaret Gondo; Mark Stephenson; Philip T. Cagle

The bcl-2 gene product inhibits apoptosis and is thought to participate in oncogenesis. Association of bcl-2 immunopositivity with improved prognosis of non-small cell lung cancers (NSCLC) is controversial. Although two studies have reported better survival in bcl-2-immunopositive NSCLCs, a third series has contradicted this finding. The authors studied a relatively larger case series involving 427 patients for whom detailed information on long-term follow-up was available to determine the prognostic significance of bcl-2 expression. The study included 252 adenocarcinomas (AC), 111 squamous cell carcinomas (SCC), and 64 large cell carcinomas (LC). After antigen retrieval, sections were immunostained using a monoclonal anti-bcl-2 antibody (1:60, Clone 124, Dako) and the avidin-biotin complex technique. Staining was scored as positive or negative and also on a semiquantitative scale as 0, low (<10%), moderate (10% to 75%), or extensive (>75%). Bcl-2 immunoreactivity was correlated with survival using the actuarial survival method, Kaplan-Meier method, and log-rank test and was not associated with statistically significant differences in survival for NSCLCs (P = .5537). Differences in survival remained insignificant even after NSCLCs were stratified for cell type, stage, or grade, singly or in combination. Therefore, using this method, bcl-2 immunopositivity does not appear to act as an independent prognostic indicator in NSCLCs.


Fertility and Sterility | 1994

High doses of oral contraceptives do not alter endometrial α1 and αvβ3 integrins in the late implantation window

Omur Taskin; Richard W. Brown; Donald C. Young; Alfred N. Poindexter; Ronald D. Wiehle

Objective To assess the effects of an emergency contraceptive agent on the distribution of integrin heterodimers during that part of the implantation window. Design Prospective, case-controlled study in a university-based Population Program. In the first ovulatory control cycle after the detection of LH surge, patients had endometrial sampling 11 days after the surge. In the next cycle the procedure was repeated 2 days after the administration of a postcoital contraceptive agent on day 9 after LH surge (100 g ethinyl E 2 and 2mg norgestrel). Main Outcome Measures The effects of postcoital contraceptives on the expression of integrin heterodimers ( α 1 and α v β 3 subunits) reported to be unique to secretory phase was determined. Results All six specimens were consistent histologically with days 24 and 25 of the menstrual cycle by light microscopy. Using immunohistochemistry, strong membrane staining of endometrial glandular cells and superficial epithelium for both α 1 subunit and vitronectin ( α v β 3) receptor was observed in treatment and controls. No diminution of intensity or distribution was observed relative to pretreatment controls. Conclusions There is no apparent change in the level of these two integrins in the human endometrium when high-dose oral contraceptives are given in the later stages of the implantation window. This suggests that the high doses of steroids used in emergency contraceptives may exert their effect through more complex mechanisms than endometrial cell surface changes.


Acta Cytologica | 1996

Ber-EP4 for differentiating adenocarcinoma from reactive and neoplastic mesothelial cells in serous effusions. Comparison with carcinoembryonic antigen, B72.3 and Leu-M1.

Michael E. Bailey; Richard W. Brown; Dina R. Mody; Philip T. Cagle; Ibrahim Ramzy

OBJECTIVE To evaluate the efficacy of Ber-EP4 in distinguishing epithelial cells from mesothelial cells in routine cytologic preparations. STUDY DESIGN Paraffin-embedded cell blocks of serous effusions from 32 patients (11 metastatic adenocarcinomas, 16 reactive mesothelial proliferations and 5 malignant mesotheliomas) were immunostained with Ber-EP4. For comparison, cell block preparations of adenocarcinomas and mesotheliomas were also immunostained with the most commonly applied markers of adenocarcinoma: carcinoembryonic antigen (CEA), B72.3 and Leu-M1. In addition, cytocentrifuge preparations of 14 reactive effusions and 2 metastatic adenocarcinomas were stained prospectively with Ber-EP4. RESULTS All adenocarcinomas showed intense membrane staining, while all mesothelial proliferations, both benign and malignant, were negative. The Ber-EP4-positive immunostaining was remarkably clean, with very minimal nonspecific staining. CEA stained 11/11 adenocarcinomas, B72.3 stained 10/11, and Leu-M1 stained 8/11; mesotheliomas were negative with all three antibodies. CONCLUSION Ber-EP4 is at least as useful as CEA, B72.3 and Leu-M1 in the diagnosis of serous effusions. It has the advantage of high sensitivity and ease of interpretation because of the high percentage of tumor cells stained, characteristic membranous staining and lack of cross-reaction with background inflammatory cells.


Human Pathology | 1996

Correlation of very late activation integrin and CD44 expression with extrarenal invasion and metastasis of renal cell carcinomas

Michael Z Gilcrease; Luan Truong; Richard W. Brown

Cell adhesion molecules mediate cell-cell and cell-matrix interactions, and they are thought to play an important role in tumor invasion and metastasis. Altered expression of integrins and CD44 in renal cell carcinoma has been recently demonstrated, but an association with invasive or metastatic behavior has not been reported. We examined very late activation (VLA) integrin and CD44 expression in 37 renal cell carcinomas and correlated adhesion molecule expression with multiple histological and clinical parameters. Most tumors exhibited positive staining for VLA3 (81%). Approximately one third of the tumors stained positively for VLA6 and CD44, and fewer (27%) were positive for VLA2. Only a few tumors were positive for VLA4 (8%) and VLA5 (14%). Most of the tumors exhibiting positive staining showed a combination of membranous and cytoplasmic staining patterns. Low-grade tumors positive for VLA6 showed a tendency for basilar staining of the tumor cells, whereas high-grade tumors exhibited diffuse cytoplasmic staining. All tumors exhibiting weak or strong positive staining for VLA4 or VLA5 showed extrarenal invasion or were known to have developed metastases at the time of nephrectomy. All tumors strongly positive for VLA2 or CD44 showed invasion beyond the renal capsule or metastases. In contrast to a previous study, no association was observed between positive staining and tumor grade. Nor were tumor size, architectural pattern, cell type, or DNA ploidy found to be associated with particular staining patterns. Although many of the invasive tumors showed no difference in VLA integrin or CD44 expression compared with tumors confined to the kidney, increased expression in some of them suggests that these cell adhesion molecules may contribute to the invasive or metastatic phenotype.


The American Journal of Surgical Pathology | 1995

Verumontanum mucosal gland hyperplasia.

Raul J. Gagucas; Richard W. Brown; Thomas M. Wheeler

Prostatic adenocarcinoma of the small acinar type can be mimicked be benign proliferative lesions, such as atypical adenomatous hyperplasia (adenosis), sclerosing adenosis, nodular hyperplasia (cellular areas), lobular hyperplasia, basal cell hyperplasia, mesonephric hyperplasia, and nephrogenic adenoma. In our study, we describe another microacinar proliferation, which we have termed verumontanum mucosal gland hyperplasia (VMGH) because it occurs exclusively in the verumontanum and adjacent posterior urethra where the ejaculatory ducts and utricle empty into the urethra. We reviewed 341 radical prostatectomies and cystoprostatectomies done from 1988 through 1993 for prostate and bladder carcinoma, respectively. Forty-nine prostates (14%) from patients aged 47 to 87 contained foci of VMGH. Of a total of 88 foci, a single lesion was present in 19 cases and multiple lesion in 30 cases. Fifty-nine of the foci arose around the ejaculatory or prostatic ducts, 17 from around the utricle, and 1κ from adjacent posterior urethral mucosa. Individual lesions were quantified as to the number of acini per focus as follows: 6 to 10 in 28(1+). 11 to 25 in 29 (2+), 25 to 50 in 16 (3+), and more than 50 in 15 (4+). No crystalloids or intraluminal mucin were seen, but: intraluminal corpora amylacea, usually numerous, were present in 57 of the 88 foci. The microacini were frequently “back to back” architecturally. The lining epithelium consisted of bland cuboidal to columnar luminal cells with underlying basal cells. VMGH, a previously undescribed benign microacinar proliferation, occurs in a very restricted and specific location and appears to be unrelated to other lesions with which it may be confused.


Cancer | 1994

Collision of transitional cell carcinoma and renal cell carcinoma. An immunohistochemical study and review of the literature.

Amy P. Hart; Richard W. Brown; Juan Lechago; Luan D. Truong

A case characterized by a rare synchronous occurrence of transitional cell carcinoma (TCC) of the renal pelvis and renal cell carcinoma (RCC) in the same kidney is presented. A retrospective analysis of 23 similar cases reported in the English literature over the last 71 years demonstrated a male‐to‐female ratio of 2:1, an average age of 64.5 years, and a left‐to‐right‐side ratio of 3.2:1. The three most common findings at initial examination were hematuria (90%), flank pain (19%), and flank mass (14%). Moreover, 24% of patients had tumor metastases even at initial examination. Thirty‐four percent of patients had bladder neoplasms, and 24% of them had a history of cigarette smoking. There is no tendency toward higher grade of malignancy or specific histologic pattern for TCC and RCC when they occur together in the same kidney. Immunohistochemical studies were used to examine TCC and RCC, with special attention paid to the site of their collision, which displayed multifocal lymphatic permeation. Both TCC and RCC were positive for epithelial membrane antigen (EMA) and cytokeratins identified by monoclonal antibodies CAM‐5.2, AE1/AE3, and MAK‐6. TCC was focally positive for keratin, detectable by antibody 34βE12, but RCC was not. The tumor tissue infiltrating the lymphatics, which seemed to be RCC, demonstrated positive staining for EMA and keratins CAM‐5.2, AE1/AE3, and MAK‐6 and negative staining for keratin 34βE12. Interestingly, the tumor in lymphatics displayed strong staining for carcinoembryonic antigen (CEA) but both TCC and RCC in the vicinity were negative. These findings suggest that keratin 34βE12 may play a role in the differential diagnosis between TCC and RCC and that tumor‐invading lymphatics may change phenotype, including the neoexpression of CEA.

Collaboration


Dive into the Richard W. Brown's collaboration.

Top Co-Authors

Avatar

Philip T. Cagle

Houston Methodist Hospital

View shared research outputs
Top Co-Authors

Avatar

Margaret Gondo

Baylor College of Medicine

View shared research outputs
Top Co-Authors

Avatar

Mamoun Younes

University of Texas at Austin

View shared research outputs
Top Co-Authors

Avatar

Mark Stephenson

Baylor College of Medicine

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Mary L. Ostrowski

Baylor College of Medicine

View shared research outputs
Top Co-Authors

Avatar

Rodolfo Laucirica

Baylor College of Medicine

View shared research outputs
Top Co-Authors

Avatar

Juan Lechago

Baylor College of Medicine

View shared research outputs
Top Co-Authors

Avatar

Luan Truong

Houston Methodist Hospital

View shared research outputs
Top Co-Authors

Avatar

Thomas M. Wheeler

Baylor College of Medicine

View shared research outputs
Researchain Logo
Decentralizing Knowledge