Marie-Louise Fjällskog

Gene expression profiling of primary male breast cancers reveals two unique subgroups and identifies N-acetyltransferase-1 (NAT1) as a novel prognostic biomarker

IntroductionMale breast cancer (MBC) is a rare and inadequately characterized disease. The aim of the present study was to characterize MBC tumors transcriptionally, to classify them into comprehensive subgroups, and to compare them with female breast cancer (FBC).MethodsA total of 66 clinicopathologically well-annotated fresh frozen MBC tumors were analyzed using Illumina Human HT-12 bead arrays, and a tissue microarray with 220 MBC tumors was constructed for validation using immunohistochemistry. Two external gene expression datasets were used for comparison purposes: 37 MBCs and 359 FBCs.ResultsUsing an unsupervised approach, we classified the MBC tumors into two subgroups, luminal M1 and luminal M2, respectively, with differences in tumor biological features and outcome, and which differed from the intrinsic subgroups described in FBC. The two subgroups were recapitulated in the external MBC dataset. Luminal M2 tumors were characterized by high expression of immune response genes and genes associated with estrogen receptor (ER) signaling. Luminal M1 tumors, on the other hand, despite being ER positive by immunohistochemistry showed a lower correlation to genes associated with ER signaling and displayed a more aggressive phenotype and worse prognosis. Validation of two of the most differentially expressed genes, class 1 human leukocyte antigen (HLA) and the metabolizing gene N-acetyltransferase-1 (NAT1), respectively, revealed significantly better survival associated with high expression of both markers (HLA, hazard ratio (HR) 3.6, P = 0.002; NAT1, HR 2.5, P = 0.033). Importantly, NAT1 remained significant in a multivariate analysis (HR 2.8, P = 0.040) and may thus be a novel prognostic marker in MBC.ConclusionsWe have detected two unique and stable subgroups of MBC with differences in tumor biological features and outcome. They differ from the widely acknowledged intrinsic subgroups of FBC. As such, they may constitute two novel subgroups of breast cancer, occurring exclusively in men, and which may consequently require novel treatment approaches. Finally, we identified NAT1 as a possible prognostic biomarker for MBC, as suggested by NAT1 positivity corresponding to better outcome.

Ki67 and cyclin A as prognostic factors in early breast cancer. What are the optimal cut-off values?

Aims:  To find the optimal cut‐off values for cyclin A and Ki67 in early breast cancer tumours and to evaluate their prognostic values.

High-resolution genomic profiling of male breast cancer reveals differences hidden behind the similarities with female breast cancer

Male breast cancer (MBC) is extremely rare and poorly characterized on the molecular level. Using high-resolution genomic data, we aimed to characterize MBC by genomic imbalances and to compare it with female breast cancer (FBC), and further to investigate whether the genomic profiles hold any prognostic information. Fifty-six fresh frozen MBC tumors were analyzed using high-resolution tiling BAC arrays. Significant regions in common between cases were assessed using Genomic Identification of Significant Targets in Cancer (GISTIC) analysis. A publicly available genomic data set of 359 FBC tumors was used for reference purposes. The data revealed a broad pattern of aberrations, confirming that MBC is a heterogeneous tumor type. Genomic gains were more common in MBC than in FBC and often involved whole chromosome arms, while losses of genomic material were less frequent. The most common aberrations were similar between the genders, but high-level amplifications were more common in FBC. We identified two genomic subgroups among MBCs; male-complex and male-simple. The male-complex subgroup displayed striking similarities with the previously reported luminal-complex FBC subgroup, while the male-simple subgroup seems to represent a new subgroup of breast cancer occurring only in men. There are many similarities between FBC and MBC with respect to genomic imbalances, but there are also distinct differences as revealed by high-resolution genomic profiling. MBC can be divided into two comprehensive genomic subgroups, which may be of prognostic value. The male-simple subgroup appears notably different from any genomic subgroup so far defined in FBC.

Expression of somatostatin receptor subtypes 1 to 5 in tumor tissue and intratumoral vessels in malignant endocrine pancreatic tumors.

Somatostatin analogs are well established in the treatment of malignant endocrine pancreatic tumors (EPTs). Our goal is to individualize their treatment using receptor-subtype-specific analogs and, therefore, exploring the receptor expression is highly important. We have examined the expression of somatostatin receptor (sst) subtypes 1–5 on tumor cells and in intratumoral vessels in 28 tumor tissues from malignant EPTs with immunohistochemistry using sst-subtype-specific polyclonal antibodies. We found that sst2 and sst4 stained positive in 90% and sst1 in 70% of the tumor tissues, whereas sst3 and sst5 stained positive in only 50% of the tumor tissues. Sst expression in intratumoral vessels was high for sst2 and sst4 (80%), moderate for sst1 (40%), and low for sst3 and sst5 (10%). The ssts were evenly distributed among the different tumor subtypes. However, tumors belonging to the same subgroup of EPTs showed a variable expression of receptor subtypes. No differences in receptor-subtype expression could be seen between poorly and well-differentiated tumors, nor between primary tumors and metastases. Prior medical treatment did not influence sst expression pattern. In conclusion, sst2 and sst4 were expressed in most tumor tissues and intratumoral vessels from EPTs. However, sst3 and sst5 were lacking in half of the tumor tissues and in most of the intratumoral vessels. These differences indicate the importance of determining each tumor’s subset of receptors before treatment with receptor-subtype-specific analogs is initiated. The importance of sst expression in intratumoral vessels is not yet known.

Treatment with Combined Streptozotocin and Liposomal Doxorubicin in Metastatic Endocrine Pancreatic Tumors

Treatment with combined streptozotocin and liposomal doxorubicin is safe and efficient in patients with endocrine pancreatic tumors (EPTs). No cardiac toxicity was reported. Background: The combination of streptozotocin and doxorubicin has been shown to be superior to streptozotocin and fluorouracil in the treatment of metastatic EPTs. However, the risk of cardiac toxicity from anthracyclins hampers the usefulness of the drug combination. Liposomal doxorubicin has a lower frequency of cardiac adverse events compared to doxorubicin. We wanted to assess the efficacy and safety of combined streptozotocin and liposomal doxorubicin in patients with metastatic EPTs. Methods: Thirty patients with metastatic EPTs were recruited from three medical centers in Norway and Sweden during a time period of 3 years. All patients had histopathologically confirmed diagnoses and bidimensionally measurable lesions. 30 mg/m2 of liposomal doxorubicin was administered on day 1 of each cycle. During the first course, 1 g of streptozotocin was given on 5 consecutive days. Thereafter, 2 g of streptozotocin was given on day 1 only. Treatment was repeated every 3 weeks. Results: Twelve of 30 patients (40%) achieved an objective radiological response with a median duration of 9 months. Stabilization of disease was achieved in 17 of 30 patients (57%) for a median duration of 11 months. Only one patient had progressive disease as best response. The 2-year progression-free survival was 18% and the 2-year overall survival was 72%. The treatment was well tolerated. None of the patients experienced cardiac toxicity. Conclusion: We conclude that combined streptozotocin and liposomal doxorubicin is a safe and efficient treatment for EPTs. The efficacy seems to be comparable to that of combined streptozotocin and doxorubicin, whereas the cardiac toxicity clearly favors using the liposomal drug combination.

Is Cremophor EL, solvent for paclitaxel, cytotoxic?

cancers, progression of in-situ cancer to invasive cancer might result from the ability of tumour cells to induce a specific functional change in some macrophage population causing migratory behaviour. Local invasion (arrested metastasis) as well as distant spread (completed metastasis) may be accomplished by such cancer-cell TAM aggregates. Thus, the close spatial relation between TAM and breast cancer cells

Upregulated expression of PDGF receptor beta in endocrine pancreatic tumors and metastases compared to normal endocrine pancreas

Platelet-derived growth factor receptor (PDGFR) beta signaling is involved in autocrine growth stimulation of tumor cells, tumor angiogenesis and regulation of tumor interstitial fluid pressure. Development of PDGFR antagonists has further increased the interest for PDGFR as targets for anticancer treatments. Malignant endocrine pancreatic tumors (EPTs) express PDGFR beta both in stroma and on tumor cells. To investigate the role of PDGFR beta signaling in EPTs we compared PDGFR beta expression in normal endocrine pancreas to malignant EPTs and metastases. PDGFR beta expression was examined by immunohistochemistry using specific polyclonal antibodies in ten tissue samples from normal endocrine pancreas, 21 from primary EPTs and 19 from metastases. In eight patients we compared the expression in normal endocrine pancreas to the corresponding primary tumor and metastases, in two patients normal tissue to the primary tumor and in 11 patients primary tumors to the corresponding metastases. Six of ten tissues containing normal pancreas stained negative for PDGFR beta on endocrine cells, while seven of ten stained positive in the stroma. Eighteen of 21 (86%) primary tumors stained positive for PDGFR beta on tumor cells and all had positive stroma stainings. All 19 metastases stained positive for PDGFR beta on tumor cells and in evaluable stroma (n=16). We have found that PDGFR beta is more frequently expressed in primary EPTs and metastases as compared to normal endocrine pancreatic tissue. This is also true for PDGFR beta expression in the corresponding stroma. We suggest that new therapeutic options to inhibit the growth and spread of EPTs could include targeting of PDGFR beta.

Cyclin B1 is a prognostic proliferation marker with a high reproducibility in a population-based lymph node negative breast cancer cohort.

A large proportion of women with lymph node negative breast cancer do not benefit from chemotherapy. Proliferation markers have been shown to recognize patients at high risk for recurrence. The Ki67 protein has recently been included in the St Gallen guidelines. The authors investigated the prognostic importance of cyclin B1 in node negative breast cancer and included a study of reproducibility. In a population‐based case‐control study, 190 women who died from breast cancer were defined as cases and 190 women alive at the time for the corresponding cases death were defined as controls. Inclusion criteria were tumor size ≤50 mm, no lymph node metastases, and no adjuvant chemotherapy. Tumor tissue was immunostained for cyclin B1. Two investigators (EN‐M and AK) evaluated the staining independently by counting approximately 100, 200, 500, and 1000 cells. Cyclin B1 was statistically significantly associated to breast cancer death, in both uni‐ and multivariate analyses (adjusted for tumor size, age, and endocrine therapy), with odds ratios 2–3 for both investigators. The agreement between the two investigators was good to very good, regardless of the number of counted cells (kappa values between 0.74 and 0.82). Cyclin B1 is a prognostic factor for breast cancer death in a population‐based node negative patient cohort which can identify high‐risk patients with a good to very good reproducibility.

Molecular subtyping of male breast cancer using alternative definitions and its prognostic impact

Abstract Background. Male breast cancer (MBC) is an uncommon disease and there is limited information on the prognostic impact of routinely used clinicopathological parameters. Material and methods. In a retrospective setting, we reviewed 197 MBC patients with accessible paraffin-embedded tumor tissue and clinicopathological data. Immunohistochemical (IHC) stainings were performed on tissue microarrays and histological grading on conventional slides. Cox proportional regression models were applied for uni- and multivariate analyses using breast cancer death as the event. Results. Estrogen receptor (ER) and progesterone receptor positivity were demonstrated in 93% and 77% of patients, respectively. Nottingham histologic grade (NHG) III was seen in 41% and HER2 positivity in 11%. Classification into molecular subtypes using IHC markers according to three alternative definitions revealed luminal A and luminal B in 81% vs. 11%; 48% vs. 44% and 41% vs. 42% of cases. Two cases of basal-like were identified, but no cases of HER2-like. Factors associated with an increased risk of breast cancer death were node positivity (HR 4.5; 95% CI 1.8–11.1), tumor size > 20 mm (HR 3.3; 95% CI 1.4–7.9) and ER negativity (HR 10.9; 95% CI 3.2–37.9). No difference in breast cancer death between the luminal subgroups was demonstrated, regardless of definition. Conclusion. MBC tumors were more often of high grade, whereas HER2 overexpression was as frequent as in FBC. Lymph nodes, tumor size and ER status were independent predictors of breast cancer death. The prognostic impact of molecular subtyping in MBC seems to differ from that previously established in FBC.

Expression of ghrelin is correlated to a favorable outcome in invasive breast cancer

Abstract Background. Expression of the peptide hormones ghrelin and obestatin has previously been demonstrated in human mammary glands. However, the clinical implications of the expression of these peptides in breast cancer are unclear. The aim of this study was to investigate the potential clinical value of ghrelin and obestatin as breast cancer biomarkers. Methods. A tissue microarray containing breast cancer specimens from 144 patients was immunostained with antibodies directed towards ghrelin and obestatin. Using varying cut-offs, the expression of the two peptides was evaluated and correlated to previously known prognostic factors in breast cancer and to the outcome. Cox regression analysis was used to assess whether these markers may predict survival of breast cancer patients. Results. Moderate to strong immunoreactivity for ghrelin and obestatin was observed in 71.5% and 77.1% of the cases, respectively. Ghrelin and obestatin expression was significantly but weakly correlated to low histological grade, estrogen receptor positivity, small tumor size and low proliferation. Only ghrelin expression was significantly correlated to better recurrence-free and breast cancer-specific survival (HR = 0.3–0.4, p = 0.02–0.05) in both uni- and multivariate analyses. The optimal cut-off was any ghrelin expression versus none. Reproducibility between the two readers was very good for both stainings with kappa values of 0.94–1.00. Conclusions. Patients with tumors expressing ghrelin had 2.5–3 times lower risk for recurrence or breast cancer death than those lacking ghrelin expression. Ghrelin expression is easily assessable with high reproducibility using immunohistochemistry. Further investigations are needed to establish the clinical significance of ghrelin as a biomarker in breast cancer.