Histopathologic review of prostate biopsies from patients referred to a comprehensive cancer center: correlation of pathologic findings, analysis of cost, and impact on treatment.

BACKGROUND: Clinicians at the Fox Chase Cancer Center (FCCC) base prostate carcinoma treatment decisions regarding need to treat, field size, total dose, and adjuvant hormonal therapy on known prognostic factors including clinical stage, Gleason score (GS), perineural invasion (PNI), and pretreatment prostate specific antigen levels. The pathology of every patient is reviewed at FCCC to confirm a diagnosis of malignancy. The objective of this study was to define differences between pathologic reviews and their impact on treatment between outside institutions and FCCC. METHODS: The authors reviewed 538 pathology reports of prostate biopsies performed at both outside pathology departments and FCCC on patients evaluated between January 1993 and December 1996. The outside pathology reviews represented 107 community hospitals, academic institutions, and private pathology laboratories. Patients who had received hormonal therapy, cryosurgery, or radical prostatectomy prior to prostate biopsy were excluded from analysis. Final FCCC pathology determinations were compared with pathology reports from outside institutions. Reports then were analyzed to determine whether differences in interpretation would have resulted in different treatment strategies. Differences in percentages according to institutional type were evaluated using the chi-square statistic. The cost was assessed and cost per change in treatment estimated. RESULTS: The 538 pathology reviews identified a nearly 40% change in GS and a 13% change in > or =2 GS between the FCCC pathology review and 107 outside academic institutions. The results of this study showed that 22% of community hospitals, 10% of private laboratories, and 8% of academic institutions demonstrated at least 2 GS changes compared with the FCCC pathology review (p = 0.001). There was no significant difference observed between types of institutions in the incidence of PNI. CONCLUSIONS: This analysis provides evidence of a significant difference in the pathologic reviews of prostate biopsies conducted at FCCC and outside pathology departments. There was a nearly 40% change in GS and a 13% change in > or =2 GS between the FCCC pathology review and 107 outside institutions. The second pathology review added approximately $104 per case for a total of $55,952 to review all 538 cases. Overall, the savings in health care dollars resulting from the second pathologic review totaled $12,997. This second review of outside pathology in prostate cancer appears to be justified based on the treatment changes and on cost.

New mechanism of action of the cancer chemotherapeutic agent 5-fluorouracil in human cells.

5-Fluorouracil (5-FlUra), a cancer chemotherapeutic agent used in the treatment of colon, breast, ovarian and prostate cancer, is incorporated into DNA as a result of its utilization as 5-FldUTP during DNA synthesis. This promutagenic DNA lesion is excised by the base excision repair enzyme uracil DNA glycosylase (UDG). In this report we describe for the first time a mechanism by which 5-FlUra as the free base specifically binds in vivo to the UDG in noncycling human cells, thereby inhibiting its activity. By using 5-FlUra concentrations which did not elicit demonstrable cell toxicity, a dose-dependent decrease in UDG activity was detected which approached 30% of that observed in control cells. In contrast, exposure of cells to equivalent concentrations of uracil, 5-fluorodeoxyuridine or 5-bromouracil had no effect on UDG activity. Subsequent studies demonstrated a reversible binding of 5-FlUra to the glycosylase. Kinetic analysis using nonlinear regression analysis demonstrated a competitive mode of inhibition and indicated a tight binding of 5-FlUra to UDG in vivo, although the 5-FlUra-UDG complex was easily dissociated in vitro. These findings describe a potentially new and novel mechanism of action of 5-FlUra in a nonproliferating human cell population. The potential relevance of these findings to the utility of 5-FlUra as a cancer chemotherapeutic agent is considered.

Cell cycle regulation of the glyceraldehyde-3-phosphate dehydrogenase/uracil DNA glycosylase gene in normal human cells.

The cell cycle regulation of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH)/uracil DNA glycosylase (UDG) gene was examined in normal human cells. Steady state RNA levels were monitored by Northern blot analysis using a plasmid (pChug 20.1) which contained the 1.3 kb GAPDH/UDG cDNA. The biosynthesis of the 37 kDa GAPDH/UDG protein was determined using an anti-human placental GAPDH/UDG monoclonal antibody to immunoprecipitate the radiolabeled protein. Increases in steady state GAPDH/UDG mRNA levels were cell cycle specific. A biphasic pattern was observed resulting in a 19-fold increase in the amount of GAPDH/UDG mRNA. The biosynthesis of the 37 kDa GAPDH/UDG protein displayed a similar biphasic regulation with a 7-fold increase. Pulse-chase experiments revealed a remarkably short half life of less than 1 hr. for the newly synthesized 37 kDa protein, comparable to that previously documented for a number of oncogenes. GAPDH/UDG mRNA levels were markedly reduced at 24 hr. when DNA synthesis was maximal. These results define the GAPDH/UDG gene as cell cycle regulated with a characteristic temporal sequence of expression in relation to DNA synthesis. The cell cycle synthesis of a labile 37 kDa monomer suggests a possible regulatory function for this multidimensional protein. Further, modulation of the GAPDH/UDG gene in the cell cycle may preclude its use as a reporter gene when the proliferative state of the cell is not kept constant.

Proliferative dependent regulation of the glyceraldehyde-3-phosphate dehydrogenase/uracil DNA glycosylase gene in human cells.

The relationship between the proliferative dependent expression of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH)/uracil DNA glycosylase (UDG) gene and the induction of uracil DNA glycosylase activity was examined in human cells. Three different cell types were studied to determine whether the growth-dependent regulation of this multifunctional gene was a common characteristic of human cells. These included WI-38 normal embryonic lung fibroblasts, a Japanese Bloom's syndrome non-transformed skin fibroblast cell strain (GM-05289) and a lymphoblastoid cell line transformed by the Epstein-Barr virus. The Japanese Bloom's syndrome cells displayed the altered immunoreactivity with marker monoclonal antibody 40.10.09 which characterizes cells from this human genetic disorder. In noncycling human cells Northern blot analysis using a plasmid (pChug 20.1) which contained the human GAPDH/UDG cDNA revealed a single 1.6 kb transcript. In each case, the expression of this gene was increased during cell proliferation. This increase in GAPDH/UDG gene expression was identical to that observed for UDG enzyme activity. Further, using anti-human UDG monoclonal antibodies, there was a growth-dependent rise in immunoreactivity suggesting an increase in the level of antigenic protein. These results demonstrate that: (i) the expression of the GAPDH/UDG gene was dependent on the proliferative state of the cell; and (ii) a correlation existed between the transcription of this gene and the level of uracil DNA glycosylase enzyme activity.