Triple-negative breast cancer in Peru: 2000 patients and 15 years of experience

Background

Epidemiological studies commonly identify the clinical characteristics and survival outcomes of patients with breast cancer at five years. Our study aims to describe the sociodemographic, clinicopathological characteristics and determine the long-term event-free survival (EFS) and overall survival (OS) of a Peruvian population with triple-negative breast cancer.

Methods

We reviewed the medical records of new cases treated at a single institution in the period 2000–2014. The survival analysis included patients with stages I-IV. Survival estimates at 10 years were calculated with the Kaplan-Meier method and compared with the Log-rank test. We further used multivariate Cox regression analysis to calculate prognostic factors of recurrence and mortality.

Results

Among the 2007 patients included, the median age at diagnosis was 49 years (19–95 years). Most patients presented histologic grade III (68.7%), tumor stage II (34.2%), and III (51.0%) at diagnosis. Local and distant relapse was present in 31.9 and 51.4% of the patients, respectively. The most frequent sites of metastasis were the lungs (14.5%), followed by bone (9.7%), brain (9.6%), and liver (7.9%). The median follow-up was 153 months. At 3, 5, and 10 years, the EFS of the population was 55%, 49%, and 41%, respectively, while the OS was 64%, 56%, and 47%, respectively. Moreover, an N3 lymph node status was the most important prognostic factor for both disease relapse (HR: 2.54, 95% CI: 2.05–3.15) and mortality (HR: 2.51, 95% CI: 2.01–3.14) at ten years. An older age and higher T staging were associated with a worse OS, while patients who received radiotherapy and adjuvant chemotherapy had better survival rates.

Conclusion

The sociodemographic features of Peruvian patients with TNBC are similar to those of other populations. However, our population was diagnosed at more advanced clinical stages, and thus, EFS and OS were lower than international reports while prognostic factors were similar to previous studies.

Lymph node ratio as best prognostic factor in triple-negative breast cancer patients with residual disease after neoadjuvant chemotherapy

Although lymph node status (ypN) is one of the most important prognostic factors of survival, the lymph node ratio (LNR) has emerged as an equitable factor. We aimed to compare the prognostic value of both ypN and LNR in patients with residual triple-negative breast cancer (TNBC) after neo-adjuvant chemotherapy (NAC). This was a retrospective cohort study of patients treated in a tertiary care center during the period 2000-2014. We stratified the population based on LNR (≤0.20, 0.20-0.65, and >0.65) and ypN (N1, N2, and N3) status. The overall survival (OS) and progression-free survival (PFS) were estimated with Kaplan-Meier curves and the log-rank + test. We further compared patient mortality and disease recurrence using multivariate Cox regression analysis. We evaluated 169 patients with a median follow-up of 87 months. At 2 years of follow-up, patients with low-risk LNR compared to those with moderate and high risk had a higher PFS (54% vs 31% vs 18%, respectively; P < .001) and OS (74% vs 64% vs 45%, respectively; P < .001). Moreover, ypN1 patients compared to ypN2 and ypN3 showed similar results in PFS (53% vs 35% vs 19%, respectively; P = .001) and OS (73% vs 69% vs 43%, respectively; P < .001). Compared to the low-risk population, patients with moderate (hazard ratio [HR]: 3.50; 95% confidence interval [CI]: 1.41-8.71) and high risk (HR: 6.90; 95% CI: 2.29-20.77) had a worse PFS. Regarding OS, moderate-risk (HR: 2.85; 95% CI: 1.10-7.38) and high-risk patients (HR: 6.48; 95% CI: 2.13-19.76) showed considerably worse outcomes. On the other hand, ypN staging was not associated with PFS or OS in the multivariate analysis. The LNR is a better prognostic factor of survival than ypN. The LNR should be considered in the stratification of risk after NAC in patients with TNBC.

Breast-conserving surgery vs. total mastectomy in patients with triple negative breast cancer in early stages: A propensity score analysis

BACKGROUND

Breast-conserving surgery (BCS) as an alternative to total mastectomy (TM) in patients with early-stage triple-negative breast cancer (TNBC) is not widely spread.

OBJECTIVE

We aimed to compare the overall survival (OS) and disease-free survival (DFS) between both surgical approaches in early-stage TNBC patients at 10 years.

METHODS

We conducted a retrospective cohort study in TNBC female patients with stage I-IIa, treated at a single-center during the period of 2000-2014. We estimated and compared the survival rates with the Kaplan Meier and Long-rank test. Propensity scores were calculated with the generalized boosted regression model and were used in the multivariate Cox regression analysis with the covariate adjustment method.

RESULTS

We included 288 patients, 111 in the BCS vs. 177 in the TM group. The median follow-up was 102 months. Moreover, the patients in the BCS group had superior OS (85% vs. 81%, p = 0.56) and DFS (83% vs. 80%, p = 0.42) at 10 years. In the multivariate Cox analysis, BCS decreased the mortality risk (HR: 0.79, 95% CI: 0.37-1.67, p = 0.538), and the locoregional or distant recurrence risk (HR: 0.67, 95% CI: 0.32-1.41, p = 0.294), albeit with no statistical significance.

CONCLUSION

BCS is a safe alternative to TM in Latin-American patients with early-stage TNBC.

Fecal pollution source tracking and thalassogenic diseases: The temporal-spatial concordance between maximum concentrations of human mitochondrial DNA in seawater and Hepatitis A outbreaks among a coastal population

Fecal pollution source tracking (FST) studies the origin of fecal contamination and promotes action to eliminate it to improve human health and environmental sustainability. This work presents the temporal and spatial relations of human mitochondrial DNA (HmtDNA), fecal coliforms (FC) and live microbial biomass (ATP) in seawater during a hepatitis A outbreak among a human coastal population. The study area is approximately 100 km along the coastline of the Biobío Region in the southeastern Pacific (Humboldt Current System, Chile). Total data from the swash zone from summer 2015 to autumn 2016 show there were significant positive log-log correlations between FC and HmtDNA (R = 0.32) and ATP (R = 0.31). These correlations were highest during the austral spring of 2015 (R = 0.53 and 0.58 respectively), when HmtDNA also correlated significantly with ATP (R = 0.86). Maximum average values of the parameters measured in this season showed a temporal-spatial concordance with the peak in the number of hepatitis A cases among the nearby coastal population. FC correlated significantly with HmtDNA (R = 0.98) in the water column of the coastal zone close to Concepción Bay during the austral summer of 2016 and in the swash zone of the bay (R = 0.68) throughout the study period. Hepatitis A virus (HAV) has also been detected in organisms and seawater in Concepción Bay, which is consistent with the high incidence of hepatitis A among the coastal population. The concordance between human fecal pollution in the study area and a seasonal hepatitis A outbreak strongly suggests that HmtDNA and its relation with FC and ATP in the coastal zone of marine environments can be used as a proxy to evaluate the risk of outbreaks of thalassogenic diseases.

Abstract 588: Neutrophil to lymphocyte ratio as strongest predictor of early death in metastatic triple negative breast cancer

Background: Metastatic triple-negative breast cancer (mTNBC) is a heterogeneous disease with poor prognosis where recent studies suggest that the immune system plays a critical role the mechanisms of disease progression and metastasis. In the other hand, a high Neutrophil to Lymphocyte Ratio (NLR) is associated with poor survival in patients diagnosed with several types of cancer. Our aim was to evaluate the prognostic value of NLR in mTNBC.

Methods: We retrospectively reviewed 130 patients diagnosed with mTNBC between 2000-2014 at “Instituto Nacional de Enfermedades Neoplasicas”. NLR group was divided in &lt;2.5 and ≥2.5. Sites of metastasis were identified by TAC or magnetic resonance imaging. Survival rates were estimated by the Kaplan-Meier method and differences were calculated by Log-rank test. The Cox Regression was used for prognostic factors.

Results: The median age was 50 years (range: 23-92 years). From our study population, 41.2% were premenopausal, and just 10 patients (9.5%) had a breast-ovary cancer familiar background, 62.5% were diagnosed at clinical stage T3-T4 and 86.1% had lymph node involvement. From 130 patients, 41 and 64 had NLR &lt;2.5 and ≥2.5, respectively, while there was no association between characteristics and NLR, only patients with malnutrition had NLR ≥2.5 (9.1% vs 40.8%, p=0.002) and solid organ involvement (62.4% vs 81.3%, p=0.04). Furthermore, lung and bone were the most frequent sites of metastasis. Those patients with lower ratio (&lt;2.5) had better response to chemotherapy (p &lt;0.001). With a median follow-up of 6.25 years, at 1-year OS was lower among patients with NLR ≥2.5 (59% vs 20%, HR: 2.77, 95%CI:1.77-4.33, p&lt;0.001). In addition, at univariate analysis malnutrition also showed an impact on OS (HR: 1.79, 95%CI: 1.20-2.67, p=0.005). At multivariate analysis, between age, T stage, N stage, NLR and solid organ involvement, just NLR was the best and only predictor of worse OS (HR: 3.12, 95%CI:1.94-5.03, p&lt;0.001). 

Conclusion: In mTNBC, an NLR ≥2.5 was a strong and accessible biomarker of poor OS. Lower values of NLR could help us to predict chemotherapy response.

Citation Format: Gabriel A. De la Cruz Ku, Zaida Morante, Joseph Pinto, Jhajaira Araujo, Daniel Enriquez, Eduardo Eyzaguirre, Antonella Saavedra, Maria Lujan, Renato Luque, Cesar Rázuri, Hugo Fuentes, Silvia Neciosup, Henry Gómez Moreno. Neutrophil to lymphocyte ratio as strongest predictor of early death in metastatic triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 588.

Abstract P3-01-07: Comparison of the prognostic value of lymph node ratio versus residual lymph node status in triple negative breast cancer

Background: Triple negative breast cancer (TNBC) patients with residual disease are characterized for a bad outcome. In these patients nodal involvement after neoadjuvant chemotherapy (NAC) is one of the most important prognostic determinants. In this study we compare two prognostic variables based on nodal status, the lymph node ratio (LNR=#positive nodes/#resected nodes) and residual lymph node status (ypN) in TNBC who received NAC.

Methods: We evaluated a retrospective cohort of TNBC patients with residual disease in the lymph nodes (at least 4 resected nodes) and treated with NAC between 2000-2014 at the Instituto Nacional de Enfermedades Neoplasicas (Lima-Peru). Patients were grouped in three LNR groups (≤0.20, 0.20-0.69 and ≥0.70). Survival differences were calculated by the log rank test. Prognostic factors for progression free survival (PFS) and overall survival (OS) were assessed by the Cox regression analysis.

Results: Overall, 189 were evaluated. Mean age was 48y (range: 26-73) where 53.5% were premenopausal and 16.5% had breast/ovary cancer familial background. A total of 175 pts (92.6%) had clinical T3-T4 tumors and 85.2% had nodal involvement at diagnosis. Indeed, the majority of patients had III CS (94.2%). Regarding to the LNR, 48.2% (n=91), 29.6% (n=56) and 22.2% (n=42) (22.2) had LNR ≤0.20, 0.21-0.69 and ≥0.70, respectively. Distribution of clinical differences was similar between groups, except for the clinical N stage (N2-N3: 15.4%, 46.4%, 52,3%, respectively; p&lt;0.001). The median follow-up was 7 years. Progression risk was higher in patients with LNR ≤0.20 than 0.20-0.69 and ≥0.70 (HR=1.77, 95%CI:1.21-2.59, p=0.003 and HR=2.22, 95%CI:1.47-3.35, respectively, p&lt;0.001). It was similar for the risk of death (HR=1.78, 95%CI: 1.17-2.70, p=0.007 and HR=2.95, 95%CI:1.91-4.56, respectively, p&lt;0.001). LNR groups were associated to progression events (P=0.02) in contrast to ypN groups (P=0.07). In the multivariate analysis, pre-menopausal status, a higher LNR and ypT with non-complete response were prognostic factors of worse DFS. Only a higher LNR has a negative impact on OS (table 1).

Conclusion: LNR was an independent prognostic factor for TNBC in patients with residual disease with better capability than ypN to predict progression events. LNR should be considered in the risk stratification after NAC among these patients.

Table 1. Multivariate Cox Regression AnalysisCharacteristicsDFS  OS   HR95%CIp valueHR95%CIp valuePremenopausal status1.931.37-2.73&lt;0.001nsnsnsLNR 0.20 vs 0.21-0.692.011.36-2.970.0011.781.17-2.700.007LNR 0.20 vs 0.701.751.57-3.74&lt;0.0012.921.88-4.55&lt;0.001ypT complete vs partial1.751.13-2.710.012nsnsnsypT complete vs non-response2.041.20-3.480.009nsnsnsns=not significant

Citation Format: De la Cruz-Ku G, Morante Z, Pinto J, Enriquez D, Eyzaguirre E, Saavedra A, Luján M, Luque R, Ramírez M, Araujo J, Fuentes H, Flores C, Moller M, Yakoub D, Neciosup S, Gomez H. Comparison of the prognostic value of lymph node ratio versus residual lymph node status in triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-01-07.

Abstract P3-10-11: Triple negative breast cancer in young Peruvian patients: 15-years' experience in a public hospital

Background: The incidence of breast cancer (BC) is low in young women and is characterized by a high prevalence of triple-negative tumors, representing a group of high risk. In this work, we describe the clinicopathological and epidemiological features of triple-negative breast cancer (TNBC) in patients aged ≤35 years.

Methods: We reviewed information of TNBC patients diagnosed at ≤35 years old and treated at the Instituto Nacional de Enfermedades Neoplasicas (between 2000 and 2014). The Cox proportional hazard model was used to identify prognostics factors for DFS and OS.

Results: In total, of 243 out 2007 cases (12.11%) were very young TNBC patients. The median follow-up was 9 years. The median age was 32 years (range: 19-35); 14.8% had obesity. A total of 40 (16.5%) patients had a family history of breast-ovary cancer (FHBOC). Regarding to the clinical-pathological characteristics, 59.4% presented T-Stages 3/4; 65.2% had nodal involvement and 7 patients (2.9%) had bilateral BC. Most of patients were diagnosed at Clinical Stage (CS) III (50.8%). The most common histological subtype the was ductal invasive carcinoma (92.1%), followed by medullar (4.5%) and lobulillar (1.7%). A high histological grade was frequent (84.7%), while 71 cases (49%) were diagnosed with vascular permeation and 55 (48.2%) with macrometastasis in lymph nodes. The majority of patients underwent mastectomy (60.2%) compared to lumpectomy (39.8%). Locoregional relapse and distant metastasis were reported in 30.9% and 49.4% of cases, respectively. The most frequent sites of metastases were lung (14.8%) and brain (11.5%). In the multivariate analysis, only N3 stage was associated with a poor outcome in terms of (N0 vs N3, HR=7.89, 95%CI:2.76-22.56, p&lt;0.001). Variables associated with the risk of death were N stage (P&lt;0.001 for N0 vs N3), neoadjuvant chemotherapy (P&lt;0.027), adjuvant chemotherapy (P&lt;0.001), and radiotherapy (P=0.008).

Conclusions: TNBC in very young Peruvian women was characterized by advanced stage at diagnosis. In these patients, nodal involvement was the most important prognostic factor for DFS. It presents distinctive characteristics and poorer outcomes in terms of DFS and OS.

Table 1. Multivariate Cox Regression Analysis.CharacteristicsPFS  OS   HR95% CIp valueHR95% CIp valueN0 vs N11.820.74-4.480.191.510.88-2.590.14N0 vs N22.260.69-7.360.183.031.69-5.46&lt;0.001N0 vs N37.892.76-22.56&lt;0.0013.581.83-7.01&lt;0.001Adjuvant chemotherapynsnsns0.340.20-0.55&lt;0.001Neo-Adjuvant Chemotherapynsnsns0.590.37-0.940.027Radiotherapynsnsns0.560.37-0.860.008ns = not significant

Citation Format: Morante Z, De la Cruz-Ku G, Pinto J, Araujo J, Eyzaguirre E, Saavedra A, Lujan M, Enriquez D, Ramirez M, Fuentes H, Neciosup S, Gomez H. Triple negative breast cancer in young Peruvian patients: 15-years' experience in a public hospital [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-11.

Abstract P1-15-02: Benefit of adjuvant chemotherapy in disease-free survival for T1N0 triple negative breast cancer

Background: Although chemotherapy is not recommended in low-risk early breast cancer, triple-negative breast cancers (TNBC) have twice risk of recurrence despite an aggressive treatment. In this study we evaluated the role of chemotherapy in the outcome of T1N0 TNBC patients in terms of disease-free survival (DFS) and overall survival (OS).

Methods: We evaluated a retrospective cohort T1N0 TNBC patients diagnosed between 2000 to 2014 at the Instituto Nacional de Enfermedades Neoplasicas (Lima-Peru). Survival rates differences were assessed by Log-rank test and prognostic factors were identified using the Cox proportional hazards model.

Results: We identified 123 T1N0 TNBC patients. The median age was 51 years (range: 28-85), where 38.5% were premenopausal. Thirty-six (29.3%) were pT1a/b and 87 were pT1c (70.7%). ACT was administered more frequently in pT1c patients (74.7% vs 55.6%; P=0.036). Locoregional relapse and distant metastases rates were 8.3% vs 19.5% and 5.6% vs 16.1% for tumors pT1a/b and pT1c, respectively. The median of follow-up was 8.8 years. Independent prognostic factors were pT stage and treatment with ACT. In relation to pT stage, DFS rates were 97% vs 78% (at 5-years) and 97% vs 70% (at 8-years) for pT1a/b vs pT1c patients, respectively (HR=4.8; 95%CI:1.46-17.0; P=0.015). In the other hand, patients treated with ACT had a better outcome with DFS rates to 5-years of 86% vs 74% and 8-years of 81% vs 65% (HR: 0.41, 95%CI: 0.17-0.97, p=0.043). Our study had not statistical power to evaluate benefit of ACT in pT1a/b patients. In cases with pT1c tumors, treatment with ACT was the only factor associated with a better DFS (HR=0.29, 95%CI: 0.11-0.77, p=0.012). Because the low mortality in our cohort, OS was not evaluable.

Conclusions: Treatment with adjuvant chemotherapy reduces the recurrence risk in 71% among pT1cN0 TNBC.

Citation Format: Morante Z, De la Cruz-Ku G, Pinto J, Araujo J, Fuentes H, Enriquez D, Luque R, Eyzaguirre E, Saavedra A, Luján M, Neciosup S, Gomez H. Benefit of adjuvant chemotherapy in disease-free survival for T1N0 triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-15-02.

Abstract P6-08-26: Outcomes and prognostic factors in 2000 patients with TNBC: Long-term results covering 10 years

Background: Triple-negative breast cancer (TNBC) is characterized by being a heterogeneous disease with different risk factors and poor survival rates. TNBC have a higher prevalence in the Peruvian population (21.3%) than in Caucasian groups. Our study aims to determine the outcome and identify prognostic factors in Peruvian women with TNBC.

Methods: We retrospectively analyzed TNBC patients treated at the “Instituto Nacional de Enfermedades Neoplasicas” between 2000 and 2014. Survival rates and differences were calculated by the Kaplan-Meier method and Log-rank test, respectively. With the Cox regression, in univariate and multivariate analysis, we identified prognostic factors in for our TNBC population.

Results: In total, 2007 patients were diagnosed.The mean age was 50 years (range: 19-95 years); 44.8% were premenopausal and 26.2% had obesity at diagnosis. A family history of breast and/or ovarian cancer was present in 266 (28.9%) patients. Regarding the clinical-pathological features, 1860 (93.5%) had ductal invasive carcinoma and 1024 (51.6%) patients were in Stage (S) III. Local relapse and distant metastasis affected to 34.5% and 51.4% of our patients, respectively. Lung (14.5%) and bone (9.7%) were the most frequent sites of metastasis. The median follow-up was 9 years. The 5 and 10 yrs DFS/OS rates are shown in table 1. In the multivariate analysis, adjuvant chemotherapy (ACT) (HR: 0.60, 95%CI: 0.44-0.82, p=0.001) and radiotherapy (RT) (HR:0.72, 95%CI:0.55-0.93, p=0.014) were associated with a reduced risk of recurrence, while nodal involvement were associated to a high recurrence risk. Factors associated to a reduction in the risk of death were ACT (HR:0.73, 95%CI:0.61-0.88, p=0.001), RT (HR: 0.70, 95%CI: 0.60-0.92, p&lt;0.001), and Neoadjuvant CT (HR: 0.61, 95%CI: 0.51-0.73, p&lt;0.001); in contrast, a NLR≥3 (HR:1.60,95%CI: 1.36-1.87, p&lt;0.001), N stage were associated with a higher risk of death.

Conclusions: Sociodemographic features of Peruvian patients with TNBC resemble other populations; however, our population is diagnosed at more advanced clinical stages, hence DFS and OS were lower than international reports while prognostic factors were similar to previous studies.

Table 1. 5- and 10-years DFS/OS ratesClinical StageIIIIIIIVTotalp (value)DFS (%)     &lt;0.0015-years837540-63 10-years696429-52 OS (%)     &lt;0.0015-years938239655 10-years837532550 

Citation Format: De la Cruz-Ku G, Morante Z, Pinto J, Enriquez D, Araujos J, Luque R, Eyzaguirre E, Saavedra A, Fuentes H, Neciosup S, Gomez H. Outcomes and prognostic factors in 2000 patients with TNBC: Long-term results covering 10 years [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-26.

Predictive value of neutrophil-to-lymphocyte ratio on pathological complete response in triple negative breast cancer

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Background: Immune response in Triple Negative Breast Cancer (TNBC) plays a critical role in pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). Therefore, neutrophil to lymphocyte ratio (NLR) could be an interesting biomarker to evaluate systemic inflammation in TNBC. Our aim was to evaluate the effect of NLR, also progression free survival (PFS) and overall survival (OS) as secondary objectives. Methods: We reviewed 338 medical records of II-III CS TNBC patients treated with NAC, in the 2000-2014 period, at Instituto Nacional de Enfermedades Neoplasicas. Patients were grouped in NLR < 3 and ≥3. Survival differences were assessed by log-rank test in the univariate analysis and prognostic factors were then investigated by Cox regression analysis. Results: Mean age was 47y [range:24-79], 54% were premenopausal, 90.9% had clinical T3-T4 tumor and 80.5% clinical nodal involvement. There were 44 and 294 pts with II and III CS, respectively. From 338 patients, 259 had NLR < 3 and 79, ≥3. No significant clinical differences were noted between these groups, except a higher mean BMI among patients with NLR < 3 (28 vs 26Kg/m2, p = 0.01). pCR rate was higher in NLR < 3 patients (22% vs 15.2%, p < 0.001) and partial response was reached on 70.7% and 62% of pts with NLR < 3 and ≥3, respectively. At 5 year median follow-up, 5-year DFS was higher among patients with NLR < 3 (47 vs 34%, HR = 0.69, 95%CI: 0.50-0.95, p = 0.02) and so was 5-year OS (55 vs 40%, HR: 0.61, CI95%: 0.43-0.85, p = 0.004). At multivariate analysis, premenopausal status, non-pCR and nodal involvement were associated with worse DFS. Otherwise, NLR < 3 (HR: 0.61, 95%CI: 0.43-0.86, p = 0.005) and pCR were predictors of better OS, nonetheless nodal involvement had negative impact on OS. Conclusions: NLR is a valuable predictive biomarker of pCR and OS in TNBC patients. We report less pCR rates due to higher stages among peruvian population.

Element enrichment factor calculation using grain-size distribution and functional data regression

In environmental geochemistry studies it is common practice to normalize element concentrations in order to remove the effect of grain size. Linear regression with respect to a particular grain size or conservative element is a widely used method of normalization. In this paper, the utility of functional linear regression, in which the grain-size curve is the independent variable and the concentration of pollutant the dependent variable, is analyzed and applied to detrital sediment. After implementing functional linear regression and classical linear regression models to normalize and calculate enrichment factors, we concluded that the former regression technique has some advantages over the latter. First, functional linear regression directly considers the grain-size distribution of the samples as the explanatory variable. Second, as the regression coefficients are not constant values but functions depending on the grain size, it is easier to comprehend the relationship between grain size and pollutant concentration. Third, regularization can be introduced into the model in order to establish equilibrium between reliability of the data and smoothness of the solutions.

Origin, patterns and anthropogenic accumulation of potentially toxic elements (PTEs) in surface sediments of the Avilés estuary (Asturias, northern Spain)

Sediment quality has been assessed within the Avilés estuary, an important industrial area in the NW of Spain. The study started with a geochemical characterization of the superficial sediments that revealed some anomalous metal(oid)s concentrations in sensitive areas such as beaches or dunes. These data were studied by means of multivariate statistical techniques and enrichment factors calculation to evaluate the correlations and geochemical origin within the different elements. A novel approach using the combination of enrichment factors with a sequential application of factor analysis, clustering and kriging was essential to identify the possible sources of pollution. The collected information suggested that Cd (strongly correlated with Zn and Pb) was the potentially toxic element most widely distributed and problematic. Furthermore, particulate emissions from Zn metallurgy, as well as dust generated by the mineral loading and stockpile activities in the port were identified as the most important sources of pollution.

Cardiovascular risk factor management is poorer in diabetic patients with undiagnosed peripheral arterial disease than in those with known coronary heart disease or cerebrovascular disease. Results of a nationwide study in tertiary diabetes centres

AIMS

To assess whether patients with Type 2 diabetes mellitus and unrecognized peripheral arterial disease (PAD), detected by the ankle-brachial index (ABI), have poorer cardiovascular risk factor management (CVRFs) and receive fewer medications than patients previously diagnosed with coronary heart disease (CHD) or cerebrovascular disease (CVD).

METHODS

In 31 diabetes centres throughout Spain, 1303 patients with Type 2 diabetes mellitus were screened for PAD using the ABI. Patient history of CHD and CVD and treatment and control of CVRFs were recorded.

RESULTS

Forty-one patients had an ABI > 1.30 and were excluded, leaving 1262 patients (age 65.3 +/- 7.7 years) for the study. Of those screened, 790 patients had a normal ABI (ABI > 0.9) and no known history of CHD or CVD (no CHD/CVD/PAD group), 194 had unrecognized PAD (ABI < or = 0.9) with no known history of CHD or CVD (undiagnosed PAD group) and 278 had a known history of CHD and/or CVD (CHD/CVD group). The undiagnosed PAD group had higher low-density lipoprotein (LDL) cholesterol (2.9 +/- 0.83 vs. 2.4 +/- 0.84 mmol/l; P < 0.001) and systolic blood pressure (150 +/- 20 vs. 145 +/- 21 mmHg; P < 0.001) compared with the CHD/CVD group. They were less likely to take statins (56.9 vs. 71.6%; P < 0.001), anti-hypertensive agents (75.9 vs. 90.1%, P = 0.001), and anti-platelet agents (aspirin, 28.7 vs. 57.2%; P < 0.001; clopidogrel, 5.6 vs. 20.9%; P < 0.001) and more likely to smoke (21.0 vs. 9.2%; P < 0.001). Higher LDL in the undiagnosed PAD group was associated with the underutilization of statins.

CONCLUSIONS

Measurement of ABI detected a significant number of patients with PAD, who did not have CHD or CVD, but whose CVRFs were under treated and poorly controlled compared with subjects with CHD and/or CVD.

A phase I-II, dose-escalating trial of ZD9331 in combination with irinotecan (CPT11) in previously pretreated metastatic colorectal cancer patients

BACKGROUND

To establish the recommended dose (RD) of the thymidylate-synthase inhibitor ZD9331 administered with irinotecan (CPT-11) in patients with pretreated metastatic colorectal cancer, and to assess toxicity profile, pharmacokinetics (PK), and anti-tumor activity in a phase I/II open, multicenter, intrapatient chemotherapy dose escalating trial.

PATIENTS AND METHODS

Twenty-one patients who failed first-line therapy (5-fluorouracil/leucovorin +/- oxaliplatin) received every 2 weeks CPT-11 180 mg/m2 D1, followed by ZD9331 30-minute infusion D2 at three dose levels: 90, 120 and 150 mg/m2.

RESULTS

RD of ZD9331 was established at 90 mg/m2 for the first two cycles, with possibility to escalate at 120 mg/m2 according to safety evaluation. Grade 3-4 toxicities were neutropenia (67% of patients), grade 3 vomiting (14%), grade 3 nausea (10%) and grade 3 diarrhea (5%). ZD9331 dose level does not affect the PK of CPT-11 or SN-38. Tumor growth control (PR + SD) was achieved for 14 (66.7%) patients. Median time to progression was 6 months, and median survival was 8.4 months.

CONCLUSION

ZD9331 90 mg/m2 combined with CPT-11 180 mg/m2 may be a viable option for treatment of metastatic colorectal cancer, with possible escalation to 120 mg/m2 of ZD9331 according to safety evaluation.

Coordinated regulation of Rap1 and thyroid differentiation by cyclic AMP and protein kinase A

Originally identified as an antagonist of Ras action, Rap1 exhibits many Ras-independent effects, including a role in signaling pathways initiated by cyclic AMP (cAMP). Since cAMP is a critical mediator of the effects of thyrotropin (TSH) on cell proliferation and differentiation, we examined the regulation of Rap1 by TSH in a continuous line of rat thyroid-like cells. Both cAMP and protein kinase A (PKA) contribute to the regulation of Rap1 activity and signaling by TSH. TSH activates Rap1 through a cAMP-mediated and PKA-independent mechanism. TSH phosphorylates Rap1 in a PKA-dependent manner. Interference with PKA activity blocked phosphorylation but not the activation of Rap1. Rather, PKA inhibitors prolonged Rap1 activation, as did expression of a Rap1A mutant lacking a PKA phosphorylation site. These results indicate that PKA elicits negative feedback regulation on cAMP-stimulated Rap1 activity in some cells. The dual regulation of Rap1 by cAMP and PKA extends to downstream effectors. The ability of TSH to stimulate Akt phosphorylation was markedly enhanced by the expression of activated Rap1A and was repressed in cells expressing a putative dominant-negative Rap1A mutant. Although the expression of activated Rap1A was sufficient to stimulate wortmannin-sensitive Akt phosphorylation, TSH further increased Akt phosphorylation in a phosphatidylinositol 3-kinase- and PKA-dependent manner. The ability of TSH to phosphorylate Akt was impaired in cells expressing a Rap1A mutant that could be activated but not phosphorylated. These findings indicate that dual signals, Rap1 activation and phosphorylation, contribute to TSH-stimulated Akt phosphorylation. Rap1 plays an essential role in cAMP-regulated differentiation. TSH effects on thyroid-specific gene expression, but not its effects on proliferation, were markedly enhanced in cells expressing activated Rap1A and repressed in cells expressing a dominant-negative Rap1A mutant. These findings reveal complex regulation of Rap1 by cAMP including PKA-independent activation and PKA-dependent negative feedback regulation. Both signals appear to be required for TSH signaling to Akt.

In vitro proliferative response of human peripheral blood mononuclear cells to concanavalin A

The proliferation response of human peripheral blood mononuclear cells (PBMC) to concanavalin A (con A) was tested in a medium with or without addition of fetal calf serum (FCS) or a serum substitute. The time profile of the proliferative response of PBMC to con A was different in cells cultured in a medium supplemented with or without FCS. This different pattern occurred for the con A-induced DNA-synthesis as well as for the RNA- or protein-synthesis. The peak proliferation rate and the stimulation index of proliferation of human PBMC to con A was also higher when the cells were cultured in a medium with 10% FCS compared to cells cultured in a FCS-free medium. Substitution of the fetal calf serum by a serum substitute even induced a profound inhibition of the de novo synthesis of DNA in human PBMC. The results indicate that a lymphocyte proliferation response to con A can still be obtained in a culture medium where no FCS was added, although a weaker stimulation occurred in comparison to a culture medium with FCS. However, addition of a serum substitute caused a marked inhibition of the lymphocyte proliferation rate.

Gap junctions play a role in the 'bystander effect' of the herpes simplex virus thymidine kinase/ganciclovir system in vitro

Tumor cells transduced with the herpes simplex virus thymidine kinase (HSVtk) gene are sensitive to the anti-viral drug ganciclovir (GCV). However, nearby untransduced tumor cells are also efficiently killed. The mechanism of this 'bystander effect' was studied by comparing pairs of tumor cell lines transfected with connexin genes that differed only in their degree of gap junctional communication. More efficient cell killing was uniformly seen in connexin transfectants compared with the less coupled cell lines. These results provide direct evidence that gap junctional communication plays an important role in mediating the bystander effect of the HSVtk/GCV system in vitro and have important prognostic and therapeutic implications for future gene therapy trials.

Changes in nutritional pattern, insulin sensitivity and glucose tolerance during weight loss in obese patients from a Mediterranean area

In order to study the nutritional pattern in obese subjects living in an area with a Mediterranean diet, as well as the modifications in nutritional behaviour, cardiovascular risk factors and insulin sensitivity induced by changes in nutritional pattern, 54 obese patients completed a 20-week behaviour programme. They prospectively fulfilled a food records diary in order to ascertain their nutritional pattern. Weight, body mass index (BMI). waist-to-hip ratio (WHR), blood pressure (BP), cholesterol, HDL-c, LDL-c, triglycerides, fasting and 2 h-post glucose load plasma glucose were determined at the onset and at the end of the study. Insulin sensitivity index (SI), and glucose effectiveness (Sg) were assessed by using the modified FSIVGTT. The usual diet in obese patients living in a Mediterranean country is low in carbohydrates (35%) and high in fats (43%), 55% of the latter being monounsaturated fatty acids (MUFAs), especially olive oil. After the educational programme they decreased the caloric intake to slightly over 700 Kcal/day, with a reduction of 36% in carbohydrates consumption, 18% in proteins and 43% in fats (46% in MUFAs). These modifications resulted in a decrease in weight, BMI, WHR, BP, and fasting and 2 h-post glucose load plasma glucose (all p < 0.05), whereas the lipoprotein profile did not change. In a similar way SI and Kg (glucose disappearance rate) increased, while fasting plasma insulin (FPI) decreased (p < 0.05) and Sg and I1+3 remained unaffected. Our results indicate that weight loss induced by caloric restriction improves insulin sensitivity rather insulin secretory capacity or glucose effectiveness, and all the cardiovascular risk factors but lipoproteic profile, that remains unchanged, probably because of the lower MUFAs consumption. These facts should be taken into account when recommending changes in the diet of obese patients with a Mediterranean-style diet.

[Antitubercular agents: pharmacogenetic factors in the development of adverse effects]

We studied the distribution of the acetylator phenotype in 47 patients aged 15 to 77 years receiving isonyazid as antituberculous therapy. 62% were fast and 32% slow acetylators. Ethnical, socio-economic and biologic factors were not related to acetylator type. The incidence of liver alterations, mainly elevated transaminase levels, was higher than reported in the literature and was not shown to be influenced by acetylator type. Adverse reactions to isonyacid were not related to drug serum levels.

[Genetic polymorphism of isoniazid acetylation in Chilean patients with tuberculosis]

We studied genetic polymorphism of isoniazid acetylation in 47 tuberculous patients treated with 4 drugs between Aug 1987 and Dec 1988. Inactivation of isoniazid was estimated from urine samples after administration of the drug (10 mg/kg). There were 18 slow and 29 fast acetylators. The frequency of the slow mutant gene was estimated at 0.612, which is intermediate between values found in american natives (0.46) and western europeans (0.73). No associations of the presence of slow gene with sex, ABO group, ancestors, socioeconomic level, undernutrition, alcoholism or tobacco consumption were found.

Cardiorespiratory inhibitory reflex induced by intravenous administration of acetaldehyde in rats

In urethane anesthetized rats, intravenous administration of a bolus of acetaldehyde (diluted 50 times its volume in Ringer Locke solution) induced after a latency of about 1 second, a triple reflex response characterized by transient bradycardia, hypotension and apnea. Intensity of both bradycardia (r = -0.78) and hypotension (r = -0.74) were dose dependent (p less than 0.001). The triple response was blocked by vagotomy. Atropine and hexamethonium blocked bradycardia and hypotension and pretreatment of rats with reserpine (0.5 mg/100 g b.wt., IP) did not change the magnitude of the reflex response. The bolus effect was discarded by injecting the same volume of Ringer Locke solution in control test experiments. Administration of acetaldehyde directly into the left ventricle induced neither bradycardia nor hypotension, thus discarding a Bezold-Jarish reflex response. Administration of acetaldehyde directly into the right ventricle induced an increase in reflex bradycardia, hypotension and apnea with a shorter latency as compared to the intravenous route. The results suggest that the response induced by acetaldehyde is mediated by a reflex increase in vagal tone and probably is initiated in pulmonary vagal afferent fibers associated with the pulmonary J receptors.

Cardiorespiratory reflex effects induced by intravenous administration of ethanol in rats

Intravenous administration of a bolus of ethanol (40 mg/100 g b.w.) to rats induced bradycardia, hypotension and apnea. Bradycardia was dose dependent (r = -0.78, p less than 0.001). Acute bilateral vagotomy blocked bradycardia and hypotension. Apnea, however, persisted in all cases but was of short duration and occurred after a significant delay as compared to an untreated group. Atropine (0.1 mg/100 g b.w.) and hexamethonium (0.75 mg/100 g b.w.) blocked bradycardia and early hypotension. Pretreatment with reserpine (0.25 mg/100 g b.w. IP 24 and 48 hours before the experiment) significantly increased bradycardia induced by ethanol as compared to untreated animals. In rats pretreated with reserpine and vagotomized, IV ethanol did not induce bradycardia, early hypotension or apnea. A bolus of ethanol (20 mg/100 g b.w.) given directly into the left ventricle did not induce reflex changes in heart rate or respiration, while the same dose of alcohol given IV decreased heart rate by 53 +/- 8.9%. Thus, the ethanol effect seems to be initiated in pulmonary J receptors. Bradycardia appeared to be mediated both by increase in vagal tone, and to a lesser extent, by sympathetic withdrawal. Hypotension was due mainly to bradycardia, and apnea might be caused by a dual mechanism, reflex (early) and direct on the respiratory center (late).

Interaction of S-carboxymethylated uteroglobin with progesterone

S-Carboxymethylated uteroglobin, a small progesterone-binding globular protein, was studied by means of high-field proton magnetic resonance spectroscopy. Conformational changes induced by the steroid have been observed and indicate a well-defined rearrangement of the structure of the protein. The unusual stoichiometry of one progesterone to two uteroglobin dimers is confirmed by 1H NMR. His-8 plays a central role in the mechanism of interaction of uteroglobin with progesterone. The pH dependence of affinity constant for the complexation of the steroid parallels the titration of this histidine. Although it is not a part of the active site, it influences a crucial conformational transition of the protein through the charge carried by its imidazole ring. Formation of a tetramer of uteroglobin subunits able to bind progesterone is critically compared to a kinetic scheme involving only dimers.