Small intestinal stromal tumors: a clinicopathologic study of 20 cases with immunohistochemical assessment of cell differentiation and the prognostic role of proliferation antigens.

Small intestinal stromal tumors (SISTs), similar to their gastric counterpart, are complex because of their divergent cellular differentiation and because of the difficulty in accurately predicting their clinical outcome. We studied a series of 22 SISTs from 20 patients to characterize lineage and investigate prognostic morphologic parameters and possible histologic and immunohistochemical differences from gastric stromal tumors (GSTs) and to determine the potential prognostic value of proliferation markers. Cases were categorized into the three following groups based on mitotic count (MC) per 50 high-power fields and tumor size: (1) benign, n = 6 (< 5 MC, < 5 cm); (2) borderline, n = 6 (< 5 MC, > or = 5 cm); and (3) malignant, n = 10 (> or = 5 MC, any size). For the formalin-fixed, paraffin-embedded tissue sections, an immunohistochemical panel was used to characterize differentiation toward myogenic cells (pan-muscle specific actin [HHF-35], alpha-smooth muscle actin, and desmin), Schwann cells (S-100 protein), enteric glial (glial fibrillary acidic protein), and nerve cells (neurofilament). Cellular proliferative activity was assessed immunohistochemically using monoclonal antibodies to proliferating cell nuclear antigen (PCNA) and Ki-67 antigen (MIB-1) and a tumor proliferation index (TPI) was obtained as the percentage of positive-staining tumor nuclei. Clinical follow-up revealed that none of the benign tumors progressed (mean follow-up, 96 months). Half of the patients with borderline tumors were dead of disease (mean, 50.7 months), while 8 of 9 patients with a malignant tumor died of disease (mean, 24.6 months). By Cox Proportional Hazard Regression analysis, mitotic count, tumor size, and cellularity significantly predicted survival. PCNA, MIB-1, tumor necrosis, and atypia were not significant predictors of survival. All tumors stained with vimentin; 17 (77%) and 13 (59%) of the tumors showed immunoreactivity with muscle-specific actin markers (HHF-35) and alpha-smooth muscle actin, respectively. Only 1 tumor stained with desmin, and none stained with S-100 protein, neurofilament, or glial fibrillary acidic protein. Immunophenotypic characteristics did not differ among the 3 groups. The TPI for PCNA and MIB-1 significantly differed between benign and malignant tumors and between borderline and malignant tumors, but it failed to separate the benign and borderline groups. Compared with 52 cases of GST previously reported by us using the same criteria and antibody panel, these tumors were histologically and immunohistochemically indistinguishable. However, none of the 18 borderline GSTs progressed, while 3 of 6 patients with a borderline SIST died of the disease. Based on this series of 22 SISTs, we conclude the following: (1) MC, size, and cellularity are the best predictors of clinical outcome in SIST. (2) The majority of SISTs show smooth muscle differentiation based on their immunoreactivity with HHF-35 and alpha-smooth muscle actin). (3) The TPI for PCNA and MIB-1 correlated with MC but failed to predict survival for individual cases. (4) SISTs and GSTs are morphologically and immunohistochemically similar; however, SISTs seem to have greater malignant potential than GSTs of similar size.

Prognostic significance of DNA ploidy and proliferation in 309 colorectal carcinomas as determined by two-color multiparametric DNA flow cytometry.

BACKGROUND: Although DNA flow cytometry has been shown to be of independent value in determining the prognosis of colorectal carcinoma, a number of well-designed studies with contradictory findings have left unresolved the clinical significance of DNA ploidy and proliferation in biologically meaningful subsets of colorectal carcinoma cases. METHODS: To evaluate the prognostic significance of DNA ploidy and proliferation as determined by flow cytometry in a prospective series of 309 human colorectal carcinomas with 4-6 years of follow-up, fresh tumors were mechanically dissociated into whole cell suspensions and dual fluorescence-labeled to allow gated analysis of subpopulations with phenotypic markers. Software programs with histogram-dependent algorithms employing background, aggregate, and debris correction were used in DNA and cell cycle quantitation. Data were analyzed according to recommendations of the 1992 DNA Flow Cytometry Consensus Conference. RESULTS: None of the clinical, site, or staging parameters, including TNM stage variables, correlated with any flow cytometric DNA ploidy or proliferation measurement. Tumors classified as DNA aneuploid or tetraploid, by any definition, did not differ in prognosis or correlate with stage or any pathologic parameter. Univariate Kaplan-Meier survival analysis showed prognostic significance of the following: Dukes staging, individual components of TNM stage (tumor depth, lymph node status, and metastasis), vascular invasion, histologic pattern of tumor infiltration, and peritumoral lymphocytic inflammation. DNA ploidy status and proliferation measurements were not predictive of survival for the overall group or within any particular stage. Only Dukes Stage D (metastasis), vascular invasion, and depth of invasion (T classification) were significant independent predictors of survival in multivariate Cox regression models. CONCLUSIONS: In this analysis, DNA ploidy and proliferation measurements were not predictive of survival in any stage of colorectal carcinoma. However, clinical and pathologic documentation of staging and select histopathologic observations were significant predictors of survival in univariate and multivariate analyses.

The effect of number of histogram events on reproducibility and variation of flow cytometric proliferation measurement.

Sources of variation in synthesis phase fraction (SPF) calculation were studied, and the number of histogram events was found to be an important quality control consideration. Six cell cycle models (CCMs) for histograms composed of 1,000 to 20,000 events were compared. All CCMs were cytometer based, or available in Multicycle (MC) software. The experiment consisted of five consecutive acquisitions, on the same day, of the same propidium iodide (PI) stained sample of T24 human cell line, at each of nine "landmarks" between 1,000 and 20,000 events. The authors found (1) all CCMs evaluated required > or = 5,000 events for accurate, reproducible SPF; and (2) in the 5,000-20,000 event range the MC models provided the most accurate, reproducible SPF values. Therefore, histogram-dependent curve fitting models may enhance clinical applications of FCM proliferation measurements. The authors conclude that histogram rejection criteria for S-phase analysis should be established, and that two-color multiparametric DNA analysis "live" gating with tissue specific markers may assure acquisition of sufficient events for accurate SPF.

Prognostic value of proliferating cell nuclear antigen index in gastric stromal tumors. Correlation with mitotic count and clinical outcome.

Morphologic studies of gastric stromal tumors (GSTs) indicate that mitotic counts (MCs) and tumor size are major discriminants predictive of biologic behavior. The authors evaluated the tumor proliferation of GSTs with anti-proliferating cell nuclear antigen (PCNA; DAKO clone PC10, DAKO Corporation, Carpinteria, CA) for correlation with MCs, histologic cell type, and clinical outcome. Fifty-eight tumors ranging from 1.5 to 45 cm in size were selected for clinicopathologic assessment. Mitotic activity was counted per 50 high-power fields (MC). For this study, combined parameters of MC and tumor size were used to categorize tumors into three groups: (1) benign: MC less than 5, tumor smaller than 5 cm; (2) borderline: MC less than 5, tumor larger than 5 cm; and (3) malignant: MC greater than 5, tumor any size. The PCNA tumor proliferation index (TPI) was assessed from evaluation of 200 tumor cells per case and expressed as the percentage of cells with positive results. Clinical follow-up was available in 45 cases. None of the 19 benign or 16 borderline tumors recurred or metastasized, whereas 7 of 10 malignant tumors metastasized and 1 of 10 recurred. The mean PCNA TPI values among benign (11.2%), borderline (16%), and malignant (34.5%) tumors were significantly different (P = 0.0002, Kruskal-Wallis test). When the pathologic tumor categories were compared, the mean TPI of benign tumors was significantly different from that of borderline tumors (P = 0.0306, Kruskal-Wallis), and the TPI of borderline tumors was different from that of the malignant tumors (P = 0.0060, Kruskal-Wallis test). The Spearman rank correlation showed a significant relationship between the MC and PCNA TPI (P = 0.0003, r = 0.4543). Logistic regression analysis showed that the TPI, independent of MC and size, contributed significantly (P = 0.00295) to the prediction of outcome. In the malignant group, the mean TPI for malignant tumors with metastases (43.6%) was significantly different (P = 0.0411, Kruskal-Wallis test) from that of malignant tumors without metastases (including the case with probable recurrence) (11.83%). No correlation was found when PCNA TPIs for epithelioid GCTs were compared with those of spindle cell GSTs.(ABSTRACT TRUNCATED AT 400 WORDS)

Prognostic significance of the nuclear DNA content in localized prostatic adenocarcinoma.

The objective of this study was to determine if the nuclear DNA content could predict disease progression in patients with stage A or B prostatic cancer. The nuclear DNA content was determined by image analysis using Feulgen-stained nuclei in tissue sections of prostatic needle biopsies from 44 patients. The patients were followed for a mean of 69.5 months, during which 12 (17%) progressed to stage D2 disease (bone or soft tissue metastases). The average times to progression to stage D2 disease were 68 months for patients who initially had stage A2 disease, 47 months for stage B1 patients and 29 months for stage B2 patients. The DNA pattern was judged diploid or normal-range (Auer type I or II histogram) in 35 tumors (80%) and aneuploid (Auer type III or IV histogram) in 9 tumors (20%). Eight (89%) of 9 tumors with an aneuploid DNA pattern and 4 (11%) of 35 tumors with a normal-range or diploid DNA pattern progressed to stage D2 disease.