Linda Werner Hartman

Fast kriging of large data sets with Gaussian Markov random fields

Spatial data sets are analysed in many scientific disciplines. Kriging, i.e. minimum mean squared error linear prediction, is probably the most widely used method of spatial prediction. Computation time and memory requirement can be an obstacle for kriging for data sets with many observations. Calculations are accelerated and memory requirements decreased by using a Gaussian Markov random field on a lattice as an approximation of a Gaussian field. The algorithms are well suited also for nonlattice data when exploiting a bilinear interpolation at nonlattice locations.

G Protein-Coupled Estrogen Receptor Is Apoptotic and Correlates with Increased Distant Disease-Free Survival of Estrogen Receptor-Positive Breast Cancer Patients

Purpose: G protein–coupled estrogen receptor 1 (GPER1), previously named GPR30, is a membrane receptor reported to mediate nongenomic estrogen responses. We investigated if GPER1 expression correlates with any clinicopathologic variables and distant disease-free survival (DDFS) in patients with breast cancer, if any prognostic impact of the receptor is dependent on estrogen receptor-α (ER-α) status, and if the receptor impacts apoptotic signaling in ER-positive breast cancer cells. Experimental Design: GPER1 expression was analyzed by immunohistochemistry in breast tumors from 273 pre- and postmenopausal stage II patients, all treated with adjuvant tamoxifen for 2 years (cohort I) and from 208 premenopausal lymph node-negative patients, of which 87% were not subjected to any adjuvant systemic treatment (cohort II). GPER1-dependent proapoptotic signaling was analyzed in MCF7 cells with and without GPER1 knockdown, T47D cells, HEK293 cells (HEK), and HEK stably expressing GPER1 (HEK-R). Results: GPER1 positively correlates with ER and progesterone receptor expression. Multivariate analysis showed that GPER1 is an independent prognostic marker of increased 10-year DDFS in the ER-positive subgroup. HEK-R has higher basal proapoptotic signaling compared with HEK including increased cytochrome C release, caspase-3 cleavage, PARP cleavage, and decreased cell viability. Treating HEK-R with the proteasome inhibitor epoxomicin, to decrease GPER1 degradation, further increases receptor-dependent proapoptotic signaling. Also, GPER1 knockdown decreases basal and agonist-stimulated proapoptotic receptor signaling in MCF7 cells. Conclusions: GPER1 is a prognostic indicator for increased DDFS in ER-positive breast cancer, which may be associated with constitutive GPER1-dependent proapoptotic signaling in ER-positive breast cancer cells. Clin Cancer Res; 19(7); 1681–92. ©2013 AACR.

Response to Radiotherapy After Breast-Conserving Surgery in Different Breast Cancer Subtypes in the Swedish Breast Cancer Group 91 Radiotherapy Randomized Clinical Trial

Purpose To evaluate the effect of adjuvant radiotherapy (RT) after breast conservation surgery in different breast cancer subtypes in a large, randomized clinical trial with long-term follow-up. Patients and Methods Tumor tissue was collected from 1,003 patients with node-negative, stage I and II breast cancer who were randomly assigned in the Swedish Breast Cancer Group 91 Radiotherapy trial between 1991 and 1997 to breast conservation surgery with or without RT. Systemic adjuvant treatment was sparsely used (8%). Subtyping was performed with immunohistochemistry and in situ hybridization on tissue microarrays for 958 tumors. Results RT reduced the cumulative incidence of ipsilateral breast tumor recurrence (IBTR) as a first event within 10 years for luminal A-like tumors (19% v 9%; P = .001), luminal B-like tumors (24% v 8%; P < .001), and triple-negative tumors (21% v 6%; P = .08), but not for human epidermal growth factor receptor 2-positive (luminal and nonluminal) tumors (15% v 19%; P = .6); however, evidence of an overall difference in RT effect between subtypes was weak ( P = .21). RT reduced the rate of death from breast cancer (BCD) for triple-negative tumors (hazard ratio, 0.35; P = .06), but not for other subtypes. Death from any cause was not improved by RT in any subtype. A hypothesized clinical low-risk group did not have a low risk of IBTR without RT, and RT reduced the rate of IBTR as a first event after 10 years (20% v 6%; P = .008), but had no effect on BCD or death from any cause. Conclusion Subtype was not predictive of response to RT, although, in our study, human epidermal growth factor receptor 2-positive tumors seemed to be most radioresistant, whereas triple-negative tumors had the largest effect on BCD. The effect of RT in the presumed low-risk luminal A-like tumors was excellent.

Immunohistochemical assessment of Ki67 with antibodies SP6 and MIB1 in primary breast cancer: a comparison of prognostic value and reproducibility.

To compare SP6 and MIB1 antibodies for assessment of Ki67 in primary breast cancer with regard to prognostic value and reproducibility.

Sex Steroid Hormone Receptor Expression Affects Ovarian Cancer Survival

Background and Aims: Although most ovarian cancers express estrogen (ER), progesterone (PR), and androgen (AR) receptors, they are currently not applied in clinical decision making. We explored the prognostic impact of sex steroid hormone receptor protein and mRNA expression on survival in epithelial ovarian cancer. Methods: Immunohistochemical stainings for ERα, ERβ, PR, and AR were assessed in relation to survival in 118 serous and endometrioid ovarian cancers. Expression of the genes encoding the four receptors was studied in relation to prognosis in the molecular subtypes of ovarian cancer in an independent data set, hypothesizing that the expression levels and prognostic impact may differ between the subtypes. Results: Expression of PR or AR protein was associated with improved 5-year progression-free (P = .001 for both) and overall survival (P < .001 for both, log-rank test). ERα and ERβ did not provide prognostic information. Patients whose tumors coexpressed PR and AR had the most favorable prognosis, and this effect was retained in multivariable analyses. Analyses of the corresponding genes using an independent data set revealed differences among the molecular subtypes, but no clear relationship between high coexpression of PGR and AR and prognosis. Conclusions: A favorable outcome was seen for patients whose tumors coexpressed PR and AR. Gene expression data suggested variable effects in the different molecular subtypes. These findings demonstrate a prognostic role for PR and AR in ovarian cancer and support that tumors should be stratified based on molecular as well as histological subtypes in future studies investigating the role of endocrine treatment in ovarian cancer.

Mammographic density in relation to tumor biomarkers, molecular subtypes, and mode of detection in breast cancer

PurposeMammographic density is an established risk factor for breast cancer; however, the relation to tumor pathological parameters including the androgen receptor and molecular subtypes has not been extensively studied.MethodsIn the Malmö Diet and Cancer Study, 733 invasive breast cancers were diagnosed from 1991 to 2007. Mammographic density was defined qualitatively. Tumor biomarker information including estrogen receptor (ER), progesterone receptor, androgen receptor (AR), human epidermal growth factor 2 (HER2), and Ki67 was collected. Surrogate molecular subtypes were defined as luminal A, luminal B, HER2 positive and triple-negative breast cancer (TNBC).ResultsAmong the 632 tumors with mammographic and pathological information, 352 tumors were screening-detected and 280 clinically detected. Higher mammographic density was associated with ER-negative tumors [ORadj 1.93 (1.04–3.59)] and TNBC [ORadj 2.44 (1.01–5.89), luminal A reference], in clinically detected breast cancer. Similarly, higher mammographic density was associated with AR-negative tumors [ORadj 1.77 (0.80–3.93)] in clinically detected breast cancer, though the evidence for this association was weak.ConclusionsIn clinically detected breast cancer, but not in screening-detected, higher mammographic density was associated with ER-negative tumors including TNBC. This study highlights the need for taking mode of detection into consideration when addressing mammographic density and tumor biomarkers.

Impact on survival of addition of etoposide to primary chemotherapy in diffuse large B-cell lymphoma: a Swedish Lymphoma Registry study

No randomised study in the rituximab era has been performed specifically to evaluate addition of etoposide to treatment of diffuse large B‐cell lymphoma (DLBCL). The aim of this study was to compare the outcome with three chemotherapy regimens (R‐CHOP‐21, R‐CHOP‐14 and R‐CHOEP‐14) in a population‐based cohort in terms of overall survival, adjusted for clinical prognostic factors. Through the Swedish Lymphoma Registry, 3443 patients with DLBCL were identified 2007–2012. Among all patients, there was no evidence of a difference between the regimens, after adjustment for prognostic factors. However, when restricted to patients aged up to 65, R‐CHOEP‐14 was associated with superior outcome compared to both R‐CHOP‐21 (hazard ratio: 0.49, 95% confidence interval: 0.3–0.9, p = 0.028) and R‐CHOP‐14 (hazard ratio: 0.64, 95% confidence interval: 0.4–1.0, p = 0.06), when adjusted for prognostic factors. Results were consistent in an additional stratified analysis with patients grouped according to age and IPI‐score. In conclusion, we could show that R‐CHOEP‐14 was associated with superior overall survival in patients with DLBCL aged up to 65 years, indicating that this may be a valid treatment option for this patient population. To further investigate which patient groups that may benefit the most from treatment intensification, R‐CHOEP‐14 should be compared to R‐CHOP‐21 in a randomised setting. Copyright

Stem cell biomarker ALDH1A1 in breast cancer shows an association with prognosis and clinicopathological variables that is highly cut-off dependent

Aims Aldehyde dehydrogenase family 1 member A1 (ALDH1A1) is a putative marker of breast cancer stem cells (CSCs) with prognostic implications when expressed in cancer or stroma. However, previous results are contradictory and we therefore aimed to further evaluate the impact of ALDH1A1 on distant disease-free survival (DDFS) and correlation with clinicopathological variables in breast cancer, specifically by evaluating different cut-offs. Methods Two breast cancer cohorts (N=216 and N=210) were evaluated with immunohistochemistry for ALDH1A1 on tissue microarrays with three different cut-offs in cancer cells and in stromal cells. The association of ALDH1A1 with DDFS and other clinicopathological variables was assessed. As further validation, gene expression levels of ALDH1A1 and association with survival were analysed in one of the cohorts and a separate cohort. Results ALDH1A1 expression in cancer cells was associated with either a better or a worse prognosis, depending on cut-off. Considering weakly stained cancer cells as positive, ALDH1A1+ was associated with a better prognosis in both cohorts. Considering only strongly stained cells as positive, ALDH1A1+ was associated with oestrogen receptor and progesterone receptor negativity in both cohorts and worse prognosis in one of the cohorts. Stromal ALDH1A1 staining was associated with improved DDFS in one cohort. Gene expression analysis showed that a high ALDH1A1 expression was associated with a better prognosis. Conclusions ALDH1A1 is associated with DDFS and clinicopathological variables, both in cancer cells and stroma, but is highly cut-off dependent. Only the strongly ALDH1A1-stained cells show a more aggressive phenotype typical for CSCs.

Do mammographic tumor features in breast cancer relate to breast density and invasiveness, tumor size, and axillary lymph node involvement?

Background Breast density and mammographic tumor features of breast cancer may carry prognostic information. The potential benefit of using the combined information obtained from breast density, mammographic tumor features, and pathological tumor characteristics has not been extensively studied. Purpose To investigate how mammographic tumor features relate to breast density and pathological tumor characteristics. Material and Methods This retrospective study was carried out within the Malmö Diet and Cancer Study: a population-based cohort study recruiting 17,035 women during 1991–1996. A total of 826 incident breast cancers were identified during follow-up. Mammography images were collected and analyzed according to breast density and tumor features at diagnosis. Pathological data were retrieved from medical reports. Mammographic tumor features in relation to invasiveness, tumor size, and axillary lymph node involvement were analyzed using logistic regression yielding odds ratios (OR) with 95% confidence intervals (CI) and adjusted for age at diagnosis, mode of detection, and breast density. Results Tumors presenting as an ill-defined mass or calcifications were more common in dense breasts than tumors presenting as a distinct mass or with spiculated appearance. Invasive cancer was more common in tumors with spiculated appearance than tumors presenting as a distinct mass (adjusted OR, 5.68 [1.81–17.84]). Among invasive tumors, an ill-defined mass was more often large (>20 mm) compared with a distinct mass, (adjusted OR, 3.16 [1.80–5.55]). Conclusion Tumors presenting as an ill-defined mass or calcifications were more common in dense breasts. Spiculated appearance was related to invasiveness, and ill-defined mass to larger tumor size, regardless of mode of detection and breast density. The potential role of mammographic tumor features in clinical decision-making warrants further investigation.

Claudin-4 Expression is Associated with Survival in Ovarian Cancer but Not with Chemotherapy Response

The tight junction protein claudin-4 has been reported to be overexpressed in advanced ovarian cancer. We investigated the prognostic significance of claudin-4 overexpression and whether claudin-4 expression could predict platinum response in primary ovarian carcinoma (OC). Claudin-4 expression was evaluated by immunohistochemistry in a tissue microarray of 140 OCs. Multivariable Cox-regression models were used to assess the effect of claudin-4 overexpression on progression-free survival and overall survival (OS). Kaplan-Meier survival analyses and the logrank test were performed comparing claudin-4 high and low groups. The association between claudin-4 expression and platinum resistance was assessed using risk ratios and the Pearson &khgr;2 test. A dataset of >1500 epithelial ovarian cancers was used to study the association between CLDN4 mRNA and survival. Of 140 evaluable cases, 71 (51%) displayed high claudin-4 expression. Claudin-4 overexpression predicted shorter 5-yr progression-free survival and OS in univariable analyses [hazard ratio (HR)=1.6 (1.1–2.5), P=0.020 and HR=1.6 (1.0–2.4), P=0.041, respectively]. Hazard of relapse was similar [HR=1.5 (1.0–2.4)] after adjustment for age, stage, type, and BRCA1/2 status in a multivariable analysis, but the evidence was slightly weaker (P=0.076). Validation in an external cohort confirmed the association between high expression of CLDN4 and poor 10-yr OS [HR=1.3 (1.1–1.5), P<0.001]. However, no confident association between claudin-4 and platinum sensitivity was found in our cohort [risk ratio=1.2 (0.7–2.0), P=0.3]. These findings suggest that high expression of claudin-4 may have a prognostic value in OC. The role of claudin-4 in the development of platinum resistance remains unclear.