Acquired expression of p27 is a favorable prognostic indicator in patients with hepatocellular carcinoma.

The p27 cyclin-dependent kinase inhibitor is a negative regulator of cell-cycle progression. In many human epithelial malignancies, decreased expression of p27 correlates with high grade, early recurrence, and poor prognosis. To evaluate the prognostic significance of p27 in hepatocellular carcinoma (HCC), we studied 54 HCCs along with corresponding nontumoral tissue. Immunohistochemistry (IHC) and Western blot (WB) analysis before and after immunoprecipitation with Cdk2 were performed on paraffin-embedded tissues and protein homogenates, respectively, to compare localization and expression of the p27 protein and to determine the total and active (Cdk2-bound) fractions of p27. Correlations were analyzed between IHC-assessed levels of p27, survival, and major clinical and pathological variables. IHC revealed no p27 expression in the majority of hepatocytes from normal and cirrhotic liver, whereas 14 HCCs (26%) were high p27 expressers (>50% positive cells), 26 (48%) low expressers (<50% positive cells), and 14 (26%) negative. High IHC signals of p27 correlated with Cdk2-bound p27 as assessed by immunoprecipitation-WB; by contrast, WB alone displayed similar levels of p27 protein in all normal and tumoral samples. High IHC p27 expression correlated with prolonged survival (P = 0.027), whereas the presence of cirrhosis was associated with poor outcome (P = 0.029). We conclude that with respect to their nonneoplastic counterparts, a subset of HCCs acquire significant p27 expression and that high expression of p27 is a favorable independent prognostic parameter for HCC.

Role of the Cdc25A phosphatase in human breast cancer.

The phosphatase Cdc25A plays an important role in cell cycle regulation by removing inhibitory phosphates from tyrosine and threonine residues of cyclin-dependent kinases, and it has been shown to transform diploid murine fibroblasts in cooperation with activated Ras. Here we show that Cdc25A is overexpressed in primary breast tumors and that such overexpression is correlated with higher levels of cyclin-dependent kinase 2 (Cdk2) enzymatic activity in vivo. Furthermore, in the breast cancer cell line MCF-7, Cdc25A activity is necessary for both the activation of Cdk2 and the subsequent induction of S-phase entry. Finally, in a series of small (< 1 cm) breast carcinomas, overexpression of Cdc25A was found in 47% of patients and was associated with poor survival. These data suggest that overexpression of Cdc25A contributes to the biological behavior of primary breast tumors and that both Cdc25A and Cdk2 are suitable therapeutic targets in early-stage breast cancer.

The cell cycle inhibitor p27 is an independent prognostic marker in small (T1a,b) invasive breast carcinomas.

Breast carcinomas < or = 1 cm in size (T1a,b) are being detected more frequently as a result of screening. Because traditional prognostic parameters are either lacking (tumor size) or rare (nodal metastases), a marker(s) is needed to identify the subset of patients who could benefit from adjuvant therapy. A retrospective series of 202 patients with stage T1a,b invasive breast carcinomas was evaluated. The clinicopathological features (age, histological grade, extensive in situ carcinoma, hormone receptor status, and nodal metastasis) as well as microvessel density and the expression of c-erb-B2, p53, MIB-1/Ki-67, and cdc25B were assessed. In addition, expression of the cell cycle inhibitor p27 was evaluated. Nineteen patients (18% of patients who had axillary dissection) had locoregional lymph node metastases. Forty-two % of them died of disease (median survival, 112 months), whereas mortality was 11% in node-negative patients (median survival, 168 months; P = 0.0055). Patients with low p27 expression had a median survival of 139 months (17% mortality) versus 174 months (9% mortality) in the group with high p27 expression (P = 0.0233). Lack of p27 was associated with poor prognosis when node-positive patients were excluded (P = 0.0252). Nodal status and low p27 were found to be the only independent prognostic parameters by both univariate and multivariate analysis, with relative risks of dying of disease of 4.9 (P = 0.001) and 3.4 (P = 0.0306), respectively. Assessment of p27, which yields prognostic information in node-negative patients, could be useful to identify patients with small, invasive breast carcinomas who might benefit from adjuvant therapy.

Increased proteasome-dependent degradation of the cyclin-dependent kinase inhibitor p27 in aggressive colorectal carcinomas.

The cell-cycle inhibitor p27 is a potential tumor suppressor, but its gene has never been found inactivated in human tumors. Because cell-cycle regulation of p27 cellular abundance occurs at the post-transcriptional level, we analyzed p27 protein expression and degradation in human colorectal carcinomas. Proteasome-mediated degradation activity of p27 was compared with its protein levels in a subset of tumor samples. We found that carcinomas with low or absent p27 protein displayed enhanced proteolytic activity specific for p27, suggesting that low p27 expression can result from increased proteasome-mediated degradation rather than altered gene expression. Patients whose tumors expressed p27 had a median survival of 151 months, whereas patients who lacked p27 (10%) had a median survival of 69 months. By multivariate analysis, p27 was found to be an independent prognostic marker. Lack of p27 was associated with poor prognosis (2.9 risk ratio for death; P = 0.003). The absence of p27 protein expression is thus a powerful negative prognostic marker in colorectal carcinomas, particularly in stage II tumors, and thereby may help in the selection of patients who will benefit from adjuvant therapy. These data suggest that aggressive tumors may result from the selection of a clone or clones that lack p27 due to increased proteasome-mediated degradation.

Sucrase-isomaltase is an independent prognostic marker for colorectal carcinoma.

PURPOSE: Expression of disaccharidase sucrase-isomaltase (SI) is significantly enhanced during neoplastic transformation of colonic epithelium. Our study was designed to determine whether expression of SI within primary tumors was significantly associated with survival in patients with colorectal carcinoma (CRC). METHODS: SI expression was analyzed by immunohistochemistry in paraffin sections from 182 Stage I to III CRC that had been resected for cure at the New England Deaconess Hospital between 1965 and 1977. Expression was scored as absent or present in 1 to 50 percent or more than 50 percent of tumor cells. Associations were explored among SI expression, other clinical or pathologic variables, and overall survival. The data set is mature, with 91 (56 percent) patients who had died of CRC at a median follow-up of 96 months. RESULTS: Fifty-five percent of primary CRC expressed SI. When the multivariate Cox analysis was performed, nodal status, T stage, primary site, grade, and SI expression were independent covariates. SI expression was not associated with the expression of other clinicopathologic variables but increased the risk of death from colorectal carcinoma by 1.83-fold. DISCUSSION: These results indicate that SI is a prognostic marker for CRC that is independent of stage-related variables in patients who have undergone potentially curative resections.

Nodular foci in parathyroid adenomas and hyperplasias: an immunohistochemical analysis of proliferative activity.

Samples of normal, hyperplastic, and neoplastic parathyroid tissues were analyzed for proliferative activity to determine (1) whether a higher number of proliferating cells were detectable in adenoma and hyperplasia versus normal tissues; (2) whether there was a difference in the number of proliferating cells in adenoma versus hyperplasia; and (3) whether there was a relationship between nodularity and proliferative rate in both adenoma and hyperplasia. Formalin-fixed, paraffin-embedded tissue from 21 patients with parathyroid adenoma and 10 patients with hyperplasia (two primary, six secondary, and two tertiary) was analyzed by immunohistochemistry with the monoclonal antibody PC10 to proliferating cell nuclear antigen (PCNA) and, in a subset of cases, with Ki-67 (MIB 1) as markers of cell proliferation. The results were that (1) no proliferating cells were found in normal glands or residual rim of "suppressed" parathyroid tissue; (2) the most intense proliferative activity was confined to nodular areas in both adenomas (57% nodular) and hyperplasias (80% nodular); (3) when fields of highest number of labeled nuclei were chosen, PCNA counts were higher in adenomas than in hyperplasia in both nodular and diffuse areas (P < .05); and (4) the number of nuclei immunoreactive for Ki-67 (MIB-1) was consistently and proportionally lower (range, 13% to 45%; mean, 32%) than the number of those immunoreactive for PCNA, although the nodular pattern was maintained. These findings demonstrate that nodules within parathyroid adenomas and hyperplasias contain subpopulations of cells with a consistently higher proliferative rate than nonnodular areas. Cells within these nodules may be more likely to develop genetic abnormalities that have been observed in hyperplastic and neoplastic parathyroid tissues.

Androgen receptor immunohistochemistry on paraffin-embedded tissue.

Androgen deprivation remains the primary therapy for patients with metastatic prostate cancer. Response to hormonal manipulation, however, has been quite variable. Androgen receptor (AR) expression has been used to predict clinical response to antiandrogenic treatment. However, methods of detection of AR expression have been limited to receptor biochemical assays in cytosolic or nuclear fractions of frozen tissue homogenates with obvious contamination problems by nonmalignant epithelial and stromal cells. As a result, studies correlating AR expression with response to hormonal therapy have been limited and controversial. More recently, immunohistochemical methods of analysis have become available, but only on frozen tissue. We describe a simple method to evaluate ARs on formalin-fixed, paraffin-embedded tissue sections using antigen retrieval methods. Primary, as well as metastatic, prostate carcinomas showed nuclear staining for ARs. Secretory cells stained uniformly in hyperplastic and normal prostatic glands. The majority of stromal cells had strong nuclear positivity. All other cancers tested (colon, breast, lung, skin, kidney) were negative. This immunohistochemical technique allows evaluation of prostate cancer AR status in routinely processed tissues. Thus, application of this technology to archival material should permit assessment of whether AR expression is predictive of response to endocrine therapy in advanced prostate cancer.