TSC2/mTORC1 signaling controls Paneth and goblet cell differentiation in the intestinal epithelium.

The intestinal mucosa undergoes a continual process of proliferation, differentiation and apoptosis, which is regulated by multiple signaling pathways. Notch signaling is critical for the control of intestinal stem cell maintenance and differentiation. However, the precise mechanisms involved in the regulation of differentiation are not fully understood. Previously, we have shown that tuberous sclerosis 2 (TSC2) positively regulates the expression of the goblet cell differentiation marker, MUC2, in intestinal cells. Using transgenic mice constitutively expressing a dominant negative TSC2 allele, we observed that TSC2 inactivation increased mTORC1 and Notch activities, and altered differentiation throughout the intestinal epithelium, with a marked decrease in the goblet and Paneth cell lineages. Conversely, treatment of mice with either Notch inhibitor dibenzazepine (DBZ) or mTORC1 inhibitor rapamycin significantly attenuated the reduction of goblet and Paneth cells. Accordingly, knockdown of TSC2 activated, whereas knockdown of mTOR or treatment with rapamycin decreased, the activity of Notch signaling in the intestinal cell line LS174T. Importantly, our findings demonstrate that TSC2/mTORC1 signaling contributes to the maintenance of intestinal epithelium homeostasis by regulating Notch activity.

NFAT5 represses canonical Wnt signaling via inhibition of ß-catenin acetylation and participates in regulating intestinal cell differentiation.

The intestinal mucosa undergoes a continual process of proliferation, differentiation, and apoptosis, which is regulated by multiple signaling pathways. The Wnt/ß-catenin pathway has a critical role in this process. Previously, we have shown that the calcineurin-dependent nuclear factor of activated T cell (NFAT) is involved in the regulation of intestinal cell differentiation, as noted by the alteration of brush-border enzyme intestinal alkaline phosphatase (IAP) activity. Here, we show that calcineurin-independent NFAT5 interacts with ß-catenin to repress Wnt signaling. We found that overexpression of NFAT5 inhibits, whereas knockdown of NFAT5 increases, TOPflash reporter activity and the expression of Wnt/ß-catenin target genes, suggesting that NFAT5 inhibits Wnt signaling. In addition, we demonstrated that NFAT5 directly interacts with the C-terminal transactivation domain (TAD) of ß-catenin, inhibits CBP interaction with ß-catenin, and inhibits CBP-mediated ß-catenin acetylation. Moreover, NFAT5 is expressed in the mucosa of human intestine, with the most pronounced staining in the most differentiated region near the epithelial surface. Knockdown of NFAT5 attenuated sodium butyrate (NaBT)-mediated induction of IAP and sucrase activities; overexpression of NFAT5 induced IAP promoter activity. In summary, we provide evidence showing that NFAT5 is a regulator of Wnt signaling. Importantly, our results suggest that NFAT5 regulation of intestinal cell differentiation may be through inhibition of Wnt/ß-catenin signaling.

Loss of PHLPP expression in colon cancer: role in proliferation and tumorigenesis.

PHLPP (PH domain leucine-rich repeats protein phosphatase) represents a family of novel Ser/Thr protein phosphatases. Two highly related isoforms in this family, PHLPP1 and PHLPP2, have been identified to serve as negative regulators of Akt and protein kinase C by dephosphorylating the kinases directly. In this study, we examined the expression pattern of both PHLPP isoforms in colorectal cancer specimens and the adjacent normal mucosa using immunohistochemical staining. We found that the expression of PHLPP1 or PHLPP2 isoform was lost or decreased in 78 and 86% of tumor tissues, respectively. Stable overexpression of either PHLPP isoform in colon cancer cells decreased the rate of cell proliferation and sensitized the cells to growth inhibition induced by the phosphoinositide-3 kinase inhibitor, LY294002, whereas knockdown of either PHLPP isoform by shRNA promoted the proliferation of DLD1 cells. In addition, we demonstrated that the PHLPP-mediated growth inhibition in colon cancer cells was largely rescued by overexpression of a constitutively active Akt. Moreover, reexpression of either PHLPP isoform in HCT116 cells inhibited tumor growth in vivo. Taken together, our results strongly support a tumor suppressor role of PHLPP in colon cancer.

Hormone receptor status of a contralateral breast cancer is independent of the receptor status of the first primary in patients not receiving adjuvant tamoxifen.

PURPOSE: To determine whether the hormone receptor status of the primary breast cancer (PBC) is predictive of the hormone receptor status of the subsequent contralateral breast cancer (CBC). PATIENTS AND METHODS: We identified patients in our database with known estrogen receptor (ER; n = 193) and/or progesterone receptor (PgR; n = 178) status in their PBC and in their subsequent CBC. One hundred twenty-six of these patients had received no adjuvant therapy, 34 had received adjuvant tamoxifen, and 33 had received adjuvant chemotherapy alone. The median interval between the first diagnosis of PBC and the development of the subsequent CBC was 3 years. ER and PgR assays were assessed biochemically in two central reference laboratories using identical quality-controlled ligand-binding methods. RESULTS: Among systemically untreated patients (n = 126), 88% of patients with ER-positive PBC and 75% of patients with ER-negative PBC developed an ER-positive CBC (P = .11). Among the tamoxifen-treated patients, those with an ER-positive PBC were almost equally likely to develop an ER-positive (47%) or ER-negative (53%) CBC (P = .99). PgR status was similar. In the untreated group (n = 112), 59% of patients with a PgR-positive PBC and 66% with a PgR-negative PBC developed a PgR-positive CBC (P = .48). Among tamoxifen-treated patients (n = 33), 50% of patients with a PgR-positive PBC versus 27% of patients with a PgR-negative PBC developed a PgR-positive CBC (P = .28). CONCLUSION: ER and PgR status of the primary tumor does not predict the hormone receptor status of the subsequent CBC in the absence of selective pressure of adjuvant therapy. Thus, other reasons should be considered to clarify the failure of tamoxifen to reduce the incidence of CBC in patients with a receptor-negative PBC.

Altered subcellular localization of suppressin, a novel inhibitor of cell-cycle entry, is an independent prognostic factor in colorectal adenocarcinomas.

PURPOSE: Suppressin (SPN), a novel inhibitor of the entry into the cell cycle, has properties of a tumor suppressor gene; however, its role in the development and progression of a human malignancy is not studied. Therefore, we evaluated the status of spn and its prognostic value in human colorectal adenocarcinoma (CRC). EXPERIMENTAL DESIGN: Inhibition of cell proliferation by exogenous/extracellular SPN was assessed by [(3)H]thymidine incorporation. The genetic status of spn in two colon cancer cell lines (LS180 and WiDr) and in a human CRC was determined using direct cDNA sequencing techniques. Phenotypic expression of SPN was evaluated in 105 CRC archival tissues using immunohistochemical methods. Univariate Kaplan-Meier and multivariate Cox proportional hazards models were used to determine the prognostic significance of SPN expression. RESULTS: Exogenous SPN inhibited the proliferation of the LS180 cell line, which also has a mutation in one allele of the spn gene. The spn gene was also mutated in the primary CRC. Expression of SPN was primarily cytoplasmic in nonmucinous CRCs and nuclear in mucinous CRCs. However, the evaluation of 85 nonmucinous CRCs demonstrated that nuclear localization of SPN, nuclear accumulation of p53, and nodal status were independent prognostic indicators with hazard ratios of 2.34, 2.33, and 3.04, respectively. Nuclear localization of SPN plus nuclear accumulation of p53 formed a stronger prognostic indicator (hazard ratios = 5.45) than local nodal status. CONCLUSIONS: This is the first report of genetic alterations in the spn gene in a human malignancy and suggests that genetic alterations in spn and the resulting immunohistochemical phenotypes based on SPN subcellular localization in CRCs may be useful in determining prognosis of patients with subtypes of CRC.

Molecular differences in mucoepidermoid carcinoma and adenoid cystic carcinoma of the major salivary glands.

OBJECTIVE/HYPOTHESIS: Mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC), the most common malignancies of the major salivary glands, are clinically and pathologically different. To determine whether MEC and ACC have different molecular characteristics, we examined the expression of erbB-2, erbB-3, epidermal growth factor receptor (EGFR), and transforming growth factor-alpha (TGF-alpha), important molecular features in other malignancies. STUDY DESIGN/METHODS: Archival tissue sections of 22 MEC and 6 ACC tumors of the major salivary glands were evaluated immunohistochemically for expression of erbB-2, erbB-3, EGRF, and TGF-alpha. A differential immunostaining score, reflecting the difference in immunostaining between carcinoma and uninvolved salivary gland tissue, was calculated for cytoplasmic and membranous staining. RESULTS: Positive immunostaining for all biomarkers was observed in the cytoplasm and membrane of both tumors. However, expression was higher in MEC than in ACC tumors and was statistically significant for cytoplasmic EGFR (P =.009), TGF-alpha (P =.041), and membranous EGFR (P =.004). A significantly higher percentage of MEC cells also demonstrated positive immunostaining for cytoplasmic erbB-3 (P =.022), EGFR (P =.005), membranous erbB-3 (P =.022), and EGFR (P =.013). The differential immunostaining score was significantly higher for MEC compared with uninvolved alveolar tissue and the membranes of uninvolved ductal tissue. There were no statistically positive differential immunostaining scores for ACC. CONCLUSIONS: There is a clear difference in the molecular phenotypes of MEC and ACC. The lack of statistically significant expression in ACC, when compared with similar uninvolved salivary gland tissue, suggests minimal involvement for these molecular structures in the pathogenesis of ACC. Conversely, erbB-2, erbB-3, EGFR, and TGF-alpha may have a role in the development and progression of MEC. These results have therapeutic implications for MEC of the major salivary glands.

Phase specific analysis of herpes zoster associated pain data: a new statistical approach.

Herpes zoster or shingles is a frequent occurrence in both elderly individuals and immunocompromised hosts. The pain associated with herpes zoster is the most debilitating complication of the disease. It can be described as acute pain and post-herpetic neuralgia or zoster associated pain (ZAP). The latter definition encompasses pain from the onset of disease through its resolution and provides a convenient analytic tool for evaluation of antiviral therapy. A heuristic examination of ZAP historical data suggests the existence of three phases of pain resolution: the acute, subacute and chronic phases. The subacute and chronic phases comprise the post-herpetic neuralgia (PHN) stage. Common analytic methods, such as a Kaplan-Meier survival function or a Cox's model, have been used to assess the pain. However, such approaches do not adequately allow for phase comparison. Notably, in the clinical trial setting the comparison of specific treatment effects on the latter stages of pain are of the greatest medical relevance since this is the most debilitating phase of the illness. In order to incorporate the phase-specific information in the modelling of time to cessation of ZAP, we assumed the hazard function was a stepwise constant. Utilizing the full likelihood function, we obtained the maximum likelihood estimate for the transition times (that is, change-points), and other parameters of medical importance. The standard error of the change-point estimates were obtained through a bootstrapping method. The asymptotic properties of the parameter estimates are also discussed. Hence, the rates of pain resolution across all phases can be examined in order to precisely define the existence of multiple phases. In addition, the covariates effect can be examined across phases and populations, thereby allowing us to translate potential efficacy of a standard therapy to different populations. These results can be utilized in the design of clinical trials or in targeting the outcome for a specific phase while controlling for the effect of other variables.

Risk factors for acquisition of hepatitis C virus infection: a case series and potential implications for disease surveillance.

BACKGROUND: Transmission of hepatitis C virus (HCV) is strongly associated with use of contaminated blood products and injection drugs. Other "non-parental" modes of transmission including sexual activity have been increasingly recognized. We examined risk factors for acquiring HCV in patients who were referred to two tertiary care centers and enrolled in an antiviral therapy protocol. METHODS: Interviews of 148 patients were conducted apart from their physician evaluation using a structured questionnaire covering demographics and risk factors for HCV acquisition. RESULTS: Risk factors (blood products, injection/intranasal drugs, razor blades/ toothbrushes, body/ear piercing, occupational exposure, sexual activity) were identified in 141 (95.3%) of participants; 23 (15.5%) had one (most frequently blood or drug exposure), 41 (27.7%) had two, and 84 (53.4%) had more than two risk factors. No patient reported sexual activity as a sole risk factor. Body piercing accounted for a high number of exposures in women. Men were more likely to have exposure to street drugs but less exposure to blood products than women. Blood product exposure was less common in younger than older HCV patients. CONCLUSION: One and often multiple risk factors could be identified in nearly all HCV-infected patients seen in a referral practice. None named sexual transmission as the sole risk factor. The development of a more complete profile of factors contributing to transmission of HCV infection may assist in clinical and preventive efforts. The recognition of the potential presence of multiple risk factors may have important implications in the approach to HCV surveillance, and particularly the use of hierarchical algorithms in the study of risk factors.

Molecular biomarkers for breast cancer prognosis: coexpression of c-erbB-2 and p53.

OBJECTIVE: To assess the prognostic significance of molecular biomarkers, particularly c-erbB-2 and p53, through study of prospective clinical data and archival breast cancer tissues for women accrued to the Alabama Breast Cancer Project. SUMMARY BACKGROUND DATA: Defining molecular abnormalities in breast cancer is an important strategy for early detection, assessment of prognosis, and treatment selection. Evidence is strong that selective biomarkers, including c-erbB-2 and p53, have prognostic significance in breast cancer. Few studies have analyzed the prognostic significance of coexpression of biomarkers. METHODS: Study patients were those accrued to the Alabama Breast Cancer Project (1975-1978) who had archival breast cancer tissues available for analysis. Criteria for entrance into the Alabama Breast Cancer Project were T1-3 breast cancer with M0 status. Age, nodal status, and histologic grade were also documented. Patients were randomized to radical versus modified radical mastectomy, and node-positive patients were also randomized to adjuvant chemotherapy (cyclophosphamide, methotrexate, and 5-fluorouracil [CMF]) versus melphalan. Archival breast cancer tissues were studied for c-erbB-2, TGF-alpha, p53, cathepsin D, bcl-2, and estrogen and progesterone receptor expression using immunohistochemistry. Survival curves were developed using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test, multivariate analysis using a rank regression model. RESULTS: Three hundred eleven patients were accrued to the Alabama Breast Cancer Project, and paraffin-embedded breast cancer tissues for 90 patients were available for immunohistochemical analysis of molecular biomarkers. Univariate analysis showed nodal status, c-erbB-2 expression, and p53 expression to have prognostic significance. Coexpression of c-erbB-2 and p53 was also found to have prognostic significance by the log-rank test. Multivariate analysis showed T stage, nodal status, c-erbB-2 expression, and p53 expression to have independent prognostic significance. CONCLUSIONS: These data suggest that c-erbB-2 and p53 expression in breast cancer have prognostic significance. After median follow-up of 16 years, coexpression of c-erbB-2 and p53 may have more prognostic significance than traditional prognostic factors such as T stage and nodal status. Prospective study of large numbers of patients with breast cancer is encouraged to validate these findings.

Bayesian monitoring of a phase 2 chemoprevention trial in high-risk cohorts for prostate cancer.

The objective of phase 2 cancer chemoprevention trials is to evaluate whether a chemopreventive agent will cause significant modulation of intermediate endpoint biomarkers (IEB) in patients at high risk for the disease. A phase 2 chemoprevention trial of 4-hydroxyphenyl retinamide (4-HPR) versus placebo was conducted in men with a histologic diagnosis of early prostate cancer and scheduled to have radical prostatectomy. A Bayesian monitoring method was used to sequentially monitor this trial for evidence of biological activity or ineffectiveness based on a single IEB variable. Different prior distributions were used and posterior distributions were obtained to calculate the probability that treatment differences are greater than or less than a predetermined clinically significant effect. The interim analysis of transforming growth factor-alpha expression indicated a high probability of insufficient biological activity of 4-HPR on this IEB. This study demonstrates the potential utility of Bayesian methods in the decision-making process in the conduct of phase 2 chemoprevention trials.

Effects of acute and chronic body weight gain reductions in the evaluation of agents for efficacy in mammary cancer prevention.

Studies were performed to determine the effects of moderate decreases in body weight gain on mammary carcinogenesis. The levels of depressions in weight gain were those often observed in the evaluation of chemopreventive agents. In the first experiment, the effects of acute and chronic reductions of body weight gain when started after carcinogen treatment were examined in young rats (MNU at 50 days of age). Significant decreases (36%) in mammary cancers occurred in groups of rats that underwent a 12% acute reduction in body weight gain as compared with ad libitum controls. In contrast, chronic weight reductions of up to 12% had minimal effects on cancer multiplicities, while a 15% chronic reduction significantly decreased cancer numbers (26%). A second experiment evaluated the efficacy of toremifene (7.0 mg/kg diet), an estrogen/anti-estrogen, and the effect of toremifene-matched body weight gain reduction that occurred during the study. Toremifene caused a chronic reduction in body weight that resulted in a 10% decrease in final body weight at the end of the study. While toremifene-treated rats exhibited a 67% decrease in the number of mammary cancers, the rats which similarly exhibited a 10% decrease in final body weight showed only a 14% decrease in cancer number. Thus, the weight effects observed with toremifene, similar estrogens/anti-estrogens, and other classes of chemopreventive compounds (where chronic body weight reductions are 10% or less) imply that the body weight reduction has a limited effect on overall chemopreventive activity. A third study examined the effect of chronic body weight gain reduction on mammary cancers induced in older rats (MNU given at 100 days of age). This model more closely resembles the status of the breast tissue of mature women currently enrolled in clinical trials of chemopreventive agents. Under these conditions chronic reductions in body weight up to 15% had minimal effects on mammary carcinogenesis. These data further demonstrated that acute body weight reductions in young rats at the time of carcinogen treatment can be a concern in interpretation of the chemopreventive activity of an agent, but that moderate chronic depressions of body weight gain probably do not play a significant role.

Fatty acid synthase: an early molecular marker of progression of prostatic adenocarcinoma to androgen independence.

PURPOSE: Changes in fatty acid synthase levels were investigated in the CWR22 xenograft model of prostatic adenocarcinoma after castration and during progression to androgen independence. MATERIALS AND METHODS: Male nude mice with CWR22 tumors were castrated and sacrificed 3, 7, 21, 28 or 42 days after castration. Some mice received testosterone replenishment 21 days after castration and were sacrificed 7 days later. In addition, other castrates were maintained for 7 to 10 months to allow tumors to relapse to androgen independence. Fatty acid synthase was measured by immunohistochemical study and Western blot analysis. RESULTS: Fatty acid synthase decreased rapidly after castration and after 28 to 42 days it was 5% to 10% of the level in tumors of intact controls. Temporal changes in fatty acid synthase after castration were associated with decreased proliferative potential and increased levels of the cyclin dependent kinase inhibitor p27Kip-1. Testosterone treatment of castrates at 21 to 28 days after castration increased fatty acid synthase expression to the level in tumors of intact controls. Tumors of long-term castrates with post-castration androgen independent growth had increased fatty acid synthase, as did small focal areas of androgen independent proliferation in tumors that had not increased in size by 7 to 10 months. In relapsed CWR22 tumors and in focal areas of androgen independent proliferation in nonrelapsed CWR22 tumors increased fatty acid synthase was associated spatially with increased proliferation and decreased p27Kip-1. CONCLUSIONS: Fatty acid synthase in CWR22 tumors depends initially on testosterone and it is associated with androgen mediated proliferation. Furthermore, increased fatty acid synthase levels associated with androgen independent proliferation may represent an early event in the development of the androgen independent phenotype.

Molecular characterization of colorectal neoplasia in translational research.

OBJECTIVE: To present recent advances in the use of molecular markers in diagnosis, in prognosis, in early detection, in novel therapies, and in understanding the molecular pathogenesis of colorectal neoplasia. DATA AND LITERATURE SOURCES: A review of studies of molecular markers in colorectal neoplasia, published in English and available on MEDLINE and BioMednet, indicates that molecular markers are being increasingly studied to predict clinical outcomes in patients with colorectal adenocarcinoma (CRC). We have used this resource, together with our published and unpublished observations at the University of Alabama at Birmingham, to provide an overview of translational research related to molecular markers in colorectal neoplasia. CONCLUSIONS: Currently, the prognosis of patients with CRC is predicted primarily on the basis of clinicopathologic staging; however, pathologists and oncology surgeons have recently begun to investigate the use of molecular markers to diagnose and/or understand the progression of CRC. In recent years, much has been learned about the molecular events responsible for the development of CRC. Also, several studies have reported the implication of some molecular markers in metastasis and tumor aggression and their usefulness in predicting clinical outcome. In this article, we discuss the use of specific molecular markers, including tumor-associated glycoprotein 72 (TAG-72), carcinoembryonic antigen (CEA), and oncofetal tumor antigens (Lewis X and Y) in diagnosis and as targets for novel therapies, as well as the phenotypic expression of bcl-2, mucin antigens (MUC1 and MUC2), and nuclear accumulation of p53 in predicting the clinical outcome of patients with CRC. We also review the ways in which molecular markers may aid the early detection of colorectal neoplasia and promote our understanding of the earliest changes in colorectal neoplasia.

Do adaptive changes in metabolic rate favor weight regain in weight-reduced individuals? An examination of the set-point theory.

BACKGROUND: Obese persons generally regain lost weight, suggesting that adaptive metabolic changes favor return to a preset weight. OBJECTIVE: Our objective was to determine whether adaptive changes in resting metabolic rate (RMR) and thyroid hormones occur in weight-reduced persons, predisposing them to long-term weight gain. DESIGN: Twenty-four overweight, postmenopausal women were studied at a clinical research center in four 10-d study phases: the overweight state (phase 1, energy balance; phase 2, 3350 kJ/d) and after reduction to a normal-weight state (phase 3, 3350 kJ/d; phase 4, energy balance). Weight-reduced women were matched with 24 never-overweight control subjects. After each study phase, assessments included RMR (by indirect calorimetry), body composition (by hydrostatic weighing), serum triiodothyronine (T(3)), and reverse T(3) (rT(3)). Body weight was measured 4 y later, without intervention. RESULTS: Body composition-adjusted RMR and T(3):rT(3) fell during acute (phase 2) and chronic (phase 3) energy restriction (P: < 0.01), but returned to baseline in the normal-weight, energy-balanced state (phase 4; mean weight loss: 12.9 +/- 2.0 kg). RMR among weight-reduced women (4771 +/- 414 kJ/d) was not significantly different from that in control subjects (4955 +/- 414 kJ/d; P: = 0.14), and lower RMR did not predict greater 4-y weight regain (r = 0.27, NS). CONCLUSIONS: Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions. Failure to establish energy balance after weight loss gives the misleading impression that weight-reduced persons are energy conservative and predisposed to weight regain. Our findings do not provide evidence in support of adaptive metabolic changes as an explanation for the tendency of weight-reduced persons to regain weight.

Racial differences in the prognostic usefulness of MUC1 and MUC2 in colorectal adenocarcinomas.

There is a need for new prognostic parameters that could add insights into the aggressiveness of tumors. Because the expression of two well-characterized mucin antigens, MUC1 and MUC2, in colorectal adenocarcinomas (CRCs) has been correlated with the aggressiveness of CRCs, we evaluated the prognostic value of the expression of MUC1 and MUC2 in CRCs collected from African-American and Caucasian patients. Expression of MUC1 and MUC2 was evaluated by immunohistochemistry in 166 archival CRC specimens collected from 58 African-American and 108 Caucasian patients that had been analyzed previously for nuclear accumulation of p53 (p53nac). Univariate Kaplan-Meier and multivariate Cox proportional hazards models were used to determine the prognostic significance of expression of MUC1 and MUC2 in these CRCs. MUC1 expression was more frequent in advanced stage CRCs, whereas MUC2 expression was higher in the mucinous type of CRCs. Although similar proportions of CRCs from African-Americans and Caucasians expressed MUC1 and MUC2, the MUC1 expression was found to be an indicator of high risk of death from CRC in Caucasians (hazard ratio, 2.03; P = 0.038) but not in African-Americans. Furthermore, Caucasians with CRCs exhibiting concomitant expression of MUC1 and p53nac demonstrated the lowest probability of overall survival (log rank test, P = 0.004). No prognostic value was found for MUC2 alone or in combination with p53nac in either group of patients. Expression of MUC1 in CRCs is a valuable indicator of poor prognosis in Caucasian patients. Additionally, combined evaluation of MUC1 and p53nac increases the ability to identify Caucasian patients with aggressive subtypes of CRC and may be useful in selecting or in developing novel therapeutic regimes.

Bcl-2 expression is associated with improved prognosis in patients with distal colorectal adenocarcinomas.

Several recent studies have suggested that the anatomic location of the tumor and ethnicity of the patient should be considered in the evaluation of prognostic markers of colorectal neoplasia. The phenotypic expression of Bcl-2 has been reported to be a useful prognostic marker in colorectal adenocarcinoma (CRC). However, its prognostic importance in CRCs based on their anatomic location and on the ethnicity of the patients has not been reported. Therefore, we evaluated Bcl-2 expression by immunohistochemistry in CRCs collected from 107 African-American and 149 Caucasian patients from a southern U.S. population. In univariate Kaplan-Meier survival analyses, Bcl-2 expression was associated with better overall survival of both African-American (log-rank, p = 0.040) and Caucasian (log-rank, p = 0.032) patients with distal but not with proximal CRCs. In multivariate Cox regression analyses, when the pathologic features of tumors were not included, the expression of Bcl-2 was associated with better survival in either ethnic patient populations with distal CRCs after adjusting for other confounding variables and p53(nac) status; however, it was not significant in either race when tumor stage was included in multivariate analyses. Thus, these studies suggest that the expression of Bcl-2 in CRCs is a valuable indicator of good prognosis in either race when CRCs are located in the distal colorectum. Also, these studies suggest that the expression of Bcl-2 is useful in determining prognosis before pathologic-clinical staging and it can aid in selection of treatment after evaluation of diagnostic biopsy specimens of patients with distal colorectal adenocarcinomas.

Longitudinal analysis of mammary cancer multiplicity in chemoprevention studies.

BACKGROUND: The effect of chemopreventive agents on cancer multiplicity is of primary interest in animal studies. The nature of data collected from chemoprevention studies may be analyzed by a longitudinal analysis of repeatedly measured cancer multiplicity data. METHODS: We determined the number of mammary cancers over the entire follow-up period for varying doses of two chemopreventive agents. Longitudinal analyses were performed to model the number of cancers over different time intervals. RESULTS: There was a significant increase in the number of cancers between six to seven weeks post-carcinogen administration in the control group. Varying patterns of cancer development were observed at different doses of chemopreventive agents including a delay in onset of tumor growth compared to the control group. CONCLUSION: Longitudinal data analysis complements traditional analyses by providing detailed information regarding the effect of chemopreventive agents on the pattern of tumor development throughout the follow-up period. Importantly, some chemopreventive agents may delay time to appearance of mammary cancers without causing a significant difference in cancer multiplicity.

Neutralization and enhancement of HIV-1 infection by sera from HIV-1 infected individuals who progress to disease at different rates.

We examined the neutralizing/enhancing activity in sera collected at an early and a later time point postinfection from 13 HIV-positive nonprogressors, 13 moderate progressors, and 13 rapid progressors to determine the relationship between neutralizing/enhancing activity and disease progression. Early sera from each group reduced virus replication at low dilutions (10(-1) to 10(-2)) when compared with negative sera. The reduction was statistically significant for moderate and rapid progressors at 10(-1) dilution (P = 0.02 and P = 0.02 respectively) but not for nonprogressors (P = 0.16). Late sera from nonprogressors and moderate progressors reduced virus replication at low dilution but late sera from rapid progressors lost neutralizing activity. These data suggest that an association exists between neutralizing activity in sera and nonprogression or slower progression to disease and that loss of neutralizing activity is associated with disease progression. At higher dilutions (10(-3) to 10(-6)), both early and late sera from each group increased virus replication over negative sera. The levels and frequency of enhancement were higher for sera from a subgroup of nonprogressors than a subgroup of rapid progressors who exhibited enhancement. This suggests that enhancement is not associated with disease progression. The neutralizing/enhancing activity observed in sera of these three groups of subjects suggest that enhancement levels may reflect the overall level of antibody response to HIV. The replication patterns observed for early and late sera from individuals in the different groups reflect changes in antibody activity that appear to be associated with protection or disease progression.

Outcome for children with supratentorial primitive neuroectodermal tumors treated with surgery, radiation, and chemotherapy.

BACKGROUND: The outcome of a child with a primitive neuroectodermal tumors arising supratentorially (SPNET) is not well characterized and may differ from the outcome of a patient with a histologically similar cerebellar tumor (medulloblastoma [MB]). Recently, 5-year progression free survival rates as high as 80% have been reported for children with MB treated with craniospinal radiation (CRT) and chemotherapy including cisplatin, lomustine (CCNU), and vincristine (VCR). METHODS: The authors reviewed the outcome of 22 consecutive patients age 3 years and older (mean age, 10 years; range, 3-18 years) with SPNET who were treated at the study institutions between 1981 and 1996. Tumor location included was 13 pineal, 6 cortical, and 3 thalamic or suprasellar. Five patients had disease dissemination at diagnosis. All patients underwent surgery and staging, followed by CRT and chemotherapy with cisplatin, CCNU, and VCR. RESULTS: Of the 22 patients, 13 had developed disease progression and 10 had died at the time of last follow-up. Overall progression free survival (PFS) was 47% +/- 11% at 3 years and 37% +/- 11% at 5 years. There was a significant difference in PFS between patients with localized disease versus those with disseminated disease (P = 0.04). There was no statistical association between tumor location and survival. Although not significant (P = 0.21), there was a trend toward better survival of those patients with complete or near-complete resection compared with those with partial resection or biopsy. CONCLUSIONS: The results of the current study demonstrate that the outcome for children with SPNET treated with radiation and chemotherapy appears worse than for children with MB treated with identical therapy. This suggests that there may be biologic differences between supratentorial and infratentorial primitive neuroectodermal tumors, thus requiring refinements in treatment.

Breast-feeding and weight change in newborns in Jamaica.

This study was conducted to examine weight change of exclusively breast-fed infants during the first week and through the first 24 days of life, and to evaluate the effect of breast-feeding factors and maternal characteristics on early weight change in the infants. The weights of 21 infants were recorded on day 1 (day of birth), and on days 3, 7, 10, 17, and 24, and the data analysed to evaluate weight change over the period. Multiple regression analysis was used to assess whether birth weight as well as maternal and breast-feeding factors were significant predictors of weight on day 24. Nineteen of the 21 infants gained weight between days 1 and 3, and 20 infants gained weight between days 3 and 7. All infants gained weight over the 24-day period and their weights at day 7 and day 24 were significantly different (P < 0.05 and P < 0.01, respectively) from their birth weights. Multiple linear regression analysis showed that significant (P < 0.01) predictors of weight gain by day 24 included birth weight, mother's educational level, whether the baby cried before feeding, and length of feeding time periods. This is the first study of weight change in the early days and weeks of life of exclusively breast-fed newborn infants in Jamaica. The infants showed significant weight gain during the study period and weight gain was affected by certain maternal and breast-feeding factors.