Ricardo Mesa-Tejada

Abnormal pattern of Tie-2 and vascular endothelial growth factor receptor expression in human cerebral arteriovenous malformations

OBJECTIVEHuman cerebral arteriovenous malformations (AVMs) are speculated to result from abnormal angiogenesis. Vascular endothelial growth factor receptors (VEGF-Rs) and Tie-2 play critical roles in vasculogenesis and angiogenesis. We hypothesized that the abnormal vascular phenotype of AVMs may be associated with abnormal expression of VEGF-Rs and Tie-2. METHODSWe measured the expression of Tie-2, VEGF-R1, and VEGF-R2 in AVMs and normal brain tissue, using immunoblotting. To assess active vascular remodeling, we also measured endothelial nitric oxide synthase expression. CD31 expression was used to control for endothelial cell mass for Tie-2, VEGF-Rs, and endothelial nitric oxide synthase. Immunoblotting data were presented as relative expression, using normal brain tissue values as 100%. RESULTSCD31 was expressed to similar degrees in AVMs and normal brain tissue (99 ± 29% versus 100 ± 20%, mean ± standard error, P = 0.98). Tie-2 expression was markedly decreased in all AVMs, compared with normal brain tissue (16 ± 9% versus 100 ± 37%, P = 0.04). VEGF-R1 expression was decreased in four of five AVMs, but the difference between the mean values was not significant (35 ± 8% versus 100 ± 42%, P = 0.14). VEGF-R2 expression was decreased in all AVMs, compared with normal brain tissue (28 ± 6% versus 100 ± 29%, P = 0.03). There was no difference in endothelial nitric oxide synthase expression between AVMs and normal brain tissue (106 ± 42% versus 100 ± 25%, P = 0.91). CONCLUSIONAVM vessels exhibited abnormal expression of Tie-2 and VEGF-Rs, both of which may contribute to the pathogenesis of AVMs.

Evidence of increased endothelial cell turnover in brain arteriovenous malformations.

OBJECTIVEWe hypothesized that human brain arteriovenous malformations (BAVMs) are nonstatic vascular lesions with active angiogenesis or vascular remodeling. To test this hypothesis, we assessed endothelial cell turnover in BAVMs. METHODSWe identified nonresting endothelial cells by use of immunohistochemistry for the Ki-67 antigen. From archived paraffin blocks, we selected BAVM vessels without intravascular thrombosis or embolic material in areas nonadjacent to the nidus edge. For controls, we used 50- to 100-&mgr;m diameter cortical vessels from temporal lobe cortex removed for epilepsy treatment. The Ki-67 index was calculated as a percentage of Ki-67-positive endothelial cells. The data were analyzed by the nonparametric Mann-Whitney test and reported as mean ± standard deviation. RESULTSThirty-seven specimens that met the above criteria were selected. There were 26 ± 15 vessels counted in each BAVM specimen versus 18 ± 5 in each control cortex (n = 5). The mean Ki-67 index was higher for BAVM vessels than control cortical vessels (0.7 ± 0.6 versus 0.1 ± 0.2%;P = 0.005), which represented an approximately seven-fold increase in the number of nonresting endothelial cells. In the BAVM group, there was a trend for younger patients to have a wider variation and higher Ki-67 index than older patients; no trend was evident in the control group. CONCLUSIONCompared with control vessels, BAVM vessels have higher endothelial cell turnover, which suggests the presence of active angiogenesis or vascular remodeling in BAVMs.

A new compllication of AIDS Thoracic myelitis caused by herpes simplex virus

Progressive thoracic myelopathy occurred in a patient with AIDS. Concurrent opportunistic infections included disseminated systemic cytomegalovims, aspergillosis, and cutaneous herpes simplex virus (HSV). At autopsy, immune stains indicated that the myelopathy was caused by HSV type 2 infection of the spinal cord.

Systems Pathology Approach for the Prediction of Prostate Cancer Progression After Radical Prostatectomy

PURPOSE For patients with prostate cancer treated by radical prostatectomy, no current personalized tools predict clinical failure (CF; metastasis and/or androgen-independent disease). We developed such a tool through integration of clinicopathologic data with image analysis and quantitative immunofluorescence of prostate cancer tissue. PATIENTS AND METHODS A prospectively designed algorithm was applied retrospectively to a cohort of 758 patients with clinically localized or locally advanced prostate cancer. A model predicting distant metastasis and/or androgen-independent recurrence was derived from features selected through supervised multivariate learning. Performance of the model was estimated using the concordance index (CI). RESULTS We developed a predictive model using a training set of 373 patients with 33 CF events. The model includes androgen receptor (AR) levels, dominant prostatectomy Gleason grade, lymph node involvement, and three quantitative characteristics from hematoxylin and eosin staining of prostate tissue. The model had a CI of 0.92, sensitivity of 90%, and specificity of 91% for predicting CF within 5 years after prostatectomy. Model validation on an independent cohort of 385 patients with 29 CF events yielded a CI of 0.84, sensitivity of 84%, and specificity of 85%. High levels of AR predicted shorter time to castrate prostate-specific antigen increase after androgen deprivation therapy (ADT). CONCLUSION The integration of clinicopathologic variables with imaging and biomarker data (systems pathology) resulted in a highly accurate tool for predicting CF within 5 years after prostatectomy. The data support a role for AR signaling in clinical progression and duration of response to ADT.

Immunoperoxidase: A sensitive immunohistochemical technique as a “special stain” in the diagnostic pathology laboratory

The present communication is a brief review of the origins, theory, and applications of a relatively new immunohistochemical technique that can be performed on routinely fixed, paraffin embedded tissues in which visualization by bright field light microscopy is feasible and which thus can be readily adapted to routine diagnostic work. The chief concern of this presentation is the practical diagnostic application of the immunoperoxidase technique, a method whose reputation as a sensitive investigative tool is well established.

Personalized Prediction of Tumor Response and Cancer Progression on Prostate Needle Biopsy

PURPOSE To our knowledge in patients with prostate cancer there are no available tests except clinical variables to determine the likelihood of disease progression. We developed a patient specific, biology driven tool to predict outcome at diagnosis. We also investigated whether biopsy androgen receptor levels predict a durable response to therapy after secondary treatment. MATERIALS AND METHODS We evaluated paraffin embedded prostate needle biopsy tissue from 1,027 patients with cT1c-T3 prostate cancer treated with surgery and followed a median of 8 years. Machine learning was done to integrate clinical data with biopsy quantitative biometric features. Multivariate models were constructed to predict disease progression with the C index to estimate performance. RESULTS In a training set of 686 patients (total of 87 progression events) 3 clinical and 3 biopsy tissue characteristics were identified to predict clinical progression within 8 years after prostatectomy with 78% sensitivity, 69% specificity, a C index of 0.74 and a HR of 5.12. Validation in an independent cohort of 341 patients (total of 44 progression events) yielded 76% sensitivity, 64% specificity, a C index of 0.73 and a HR of 3.47. Increased androgen receptor in tumor cells in the biopsy highly significantly predicted resistance to therapy, ie androgen ablation with or without salvage radiotherapy, and clinical failure (p <0.0001). CONCLUSIONS Morphometry reliably classifies Gleason pattern 3 tumors. When combined with biomarker data, it adds to the hematoxylin and eosin analysis, and prostate specific antigen values currently used to assess outcome at diagnosis. Biopsy androgen receptor levels predict the likelihood of a response to therapy after recurrence and may guide future treatment decisions.

Carcinoembryonic antigen in gynecologic patients: I. Correlation of plasma levels and tissue localization☆

Abstract Plasma levels of carcinoembryonic antigen (CEA) were measured in 36 patients with suspected gynecologic malignancies from whom histological tissues were available for antigenic localization. The latter was done utilizing the three-layer bridge immunoperoxidase technique for paraffin sections. The presence or absence of tissue CEA as determined by this method is correlated with the plasma levels of CEA in each patient.

Automated localization and quantification of protein multiplexes via multispectral fluorescence imaging

We present a new system for automated localization and quantification of the expression of protein biomarkers in immunofluorescence (IF) microscopic images. The system includes a novel method for discriminating the biomarker signal from background, where signal may be the expression of any of the many biomarkers or counterstains used in IF. The method is based on supervised learning and represents the biomarker intensity threshold as a function of image background characteristics. The utility of the proposed system is demonstrated in predicting prostate cancer recurrence in patients undergoing prostatectomy. Specifically, features representing androgen receptor (AR) expression are shown to be statistically significantly associated with poor outcome in univariate analysis. AR features are also shown to be valuable for multivariate recurrence prediction.

Diagnosis of primary breast carcinoma through immunohistochemical detection of antigen related to mouse mammary tumor virus in metastatic lesions: A report of two cases

Recent investigations have established that approximately half of human breast carcinomas contain an immunohistochemically detectable antigen which is cross‐reactive with the 52000‐dalton major glycoprotein (gp52) of the mouse mammary tumor virus (MMTV). This antigen can be localized in paraffin‐embedded sections of routinely fixed tissues using heterologous antibodies to gp52 or MMTV. This report describes two patients with metastatic carcinoma in axillary lymph nodes without any clinical evidence of a primary lesion in the breast or elsewhere. The localization of the gp52‐related antigen in paraffin‐embedded sections of both metastatic lesions suggested the presence of primary mammary carcinoma. In both instances, this suggestion was ultimately confirmed by the finding of primary lesions in which the gp52‐related antigen was also found.

Possible diagnostic implications of a mammary tumor virus related protein in human breast cancer.

An antigen immunologically related to gp52, a 52,000‐dalton glycoprotein of the mouse mammary tumor virus, has been identified with monospecific IgG in sections of human breast cancer by the indirect immunoperoxidase technique. The cross‐reactivity between the human tumor antigen and the murine gp52 has been shown to be due to the polypeptide rather than to the polysaccharide components of gp52. The specificity of the reaction has been established by absorption experiments, which revealed that only purified gp52, or material containing it, served to eliminate the IgG molecules responsible for the immunohistochemical reaction. Further, positive responses are seen only in breast carcinomas, being absent in benign breast lesions (e.g., cystic disease, fibroadenoma, papilloma) and in normal breast tissue.