Faculty Bibliography

A recent study by Morgan et al. on the mechanism of the heating antigen retrieval (AR) has raised an interesting issue concerning calcium-induced modification of protein conformation demonstrated by immunohistochemistry (IHC). The current study is based on calcium-induced modification of thrombospondin (TSP) and Ki-67, as demonstrated by IHC using seven monoclonal antibodies (MAbs) to TSP and an MAb MIB1. Experiments were carried out on frozen tissue sections of bladder carcinoma and lymph node. Frozen sections were incubated with solutions of 50 mM CaCl2 and/or 10 mM EDTA at 4C overnight before formalin or acetone fixation for TSP and Ki-67, respectively. Sections were then fixed in 10% neutral buffered formalin or acetone before immunostaining. Seven MAbs to TSP, named Ab1 to 7 representing clone numbers of A4.1, D4.6, C6.7, A6.1, B5.2, A2.5, and HB8432, respectively, and MIB1 were utilized as primary antibodies. ABC was used as the detection system and AEC as the chromogen for immunohistochemical staining. An extracellular immunostaining pattern represented a positive result for TSP, and nuclear staining for MIB1. Frozen sections preincubated in 50 mM CaCl2 overnight at 4C showed significant loss of staining and/or altered staining pattern for six of the seven antibodies to TSP and MIB1 compared to positive controls not exposed to CaCl2. Lack of immunostaining of TSP and MIB1 attributable to exposure to CaCl2 could be partially recovered by incubating the frozen sections in EDTA. Calcium-induced modification of protein structure was demonstrated more than 10 years ago on the basis of immunochemical techniques. In this study, similar calcium-induced modification of protein was detectable by IHC in frozen tissue sections, suggesting that calcium-induced modification of protein structure may occur independently of fixation-induced modification. The fact that calcium binding may affect IHC staining is not surprising in view of the fact that antibody/antigen interactions are protein structure-dependent. However, in this experiment the change occurred before and independent of formalin fixation and does not necessarily imply a role for calcium in AR. There may be a valuable role for the use of chemical modification in visualization of protein structure changes in tissue sections by IHC. (J Histochem Cytochem 47:463-469, 1999)

BACKGROUND:There are few biologic determinants that are prognostic for patients with localized prostate cancer. We examined whether cellular levels of the cyclin-kinase inhibitor p27Kip1 (also known as p27) in prostate tumors could be used to predict progression of this disease. METHODS:Levels of p27 in tumor cell nuclei were assessed by immunohistochemical analysis of tissue sections from the primary tumors of 96 patients with stage C prostate carcinoma who had been treated by radical prostatectomy. Tumors were classified into one of the following three groups on the basis of the percentage of tumor cells showing nuclear p27 reactivity: low (0%-10%), moderate (11%-50%), and high (>50%). The Mantel-Haenszel test, Kaplan-Meier analysis, and the logrank test were used to calculate the probability that nuclear p27 levels were associated with tumor grade and substage, with a serum prostate-specific antigen (PSA) recurrence (defined as the finding of a detectable level [0.4 ng/mL or greater] of serum PSA following radical prostatectomy), with the recurrence of clinically evident disease, and with survival. All reported P values are two-sided. RESULTS:Luminal cells and basal cells of normal prostate glands showed high levels of nuclear p27 immunoreactivity in all tissue sections examined. Fifty-three tumors showed high p27 reactivity, 31 showed moderate reactivity, and 12 showed low or no detectable reactivity. Decreased levels of p27 were associated with tumor grade (P = .004). Tumor levels of p27 were not associated with preoperative prostate-specific antigen levels (P = .360) or with tumor substage (P = .320). However, decreased p27 reactivity was significantly associated with an increased probability of recurrence (P = .004) and decreased survival (P = .010). The median recurrence-free interval for patients with tumors showing high, moderate, or low p27 reactivity was 13.7 years, 8.4 years, and 4.7 years, respectively. Median survival times were more than 14 years, more than 13.5 years, and 8.1 years for patients in the high, moderate, and low p27 reactivity groups, respectively. CONCLUSION/CONCLUSIONS:Levels of nuclear p27 immunoreactivity in the primary tumor can be used to predict recurrence and survival among patients with localized prostate cancer.

180 cases of vascular malformation in brain (BVM) including 156 cases of brain biopsy and 24 autopsy cases were examined with routine pathological methods. The attempt of this study is to realize the pathological change and incidnce of each type and to find out the main cause of hemorrhage in BVM. According the morphological characteristics, 180 cases of BVM were classified into five types. They are: arteriovenous type 159 cases, venous type 3 cases, cavernous type 6 cases, capillary telangiectasis 1 case, and mixed type 11 cases. Hemorrhage was the most common clinical manifestation and main cause of death in BVM. The mechanism of hemorrhage may be due to either hemodynamic disturbance in local area or changes of the blood vessel wall. Besides these, there are five cases of BVM accompanied with brain tumor. They may be two independent diseases occurred in the same person. No relationship was found between the occurrence of these 2 entities.