A prognostic model based on cell-cycle control predicts outcome of breast cancer patients

Background

A prognostic model combining biomarkers of metaphase-anaphase transition of the cell cycle was developed for invasive breast cancer. The prognostic value and clinical applicability of the model was evaluated in comparison with the routine prognosticators of invasive breast carcinoma.

Methods

The study comprised 1135 breast cancer patients with complete clinical data and up to 22-year follow-up. Regulators of metaphase-anaphase transition were detected immunohistochemically and the biomarkers with the strongest prognostic impacts were combined into a prognostic model. The prognostic value of the model was tested and evaluated in separate patient materials originating from two Finnish breast cancer centers.

Results

The designed model comprising immunoexpressions of Securin, Separase and Cdk1 identified 8.4-fold increased risk of breast cancer mortality (p < 0.0001). A survival difference exceeding 15 years was observed between the majority (> 75%) of patients resulting with favorable as opposed to unfavorable outcome of the model. Along with nodal status, the model showed independent prognostic impact for all breast carcinomas and for subgroups of luminal, N+ and N- disease.

Conclusions

The impact of the proposed prognostic model in predicting breast cancer survival was comparable to nodal status. However, the model provided additional information in N- breast carcinoma in identifying patients with aggressive course of disease, potentially in need of adjuvant treatments. Concerning N+, in turn, the model could provide evidence for withholding chemotherapy from patients with favorable outcome.

UBR5 Is Coamplified with MYC in Breast Tumors and Encodes an Ubiquitin Ligase That Limits MYC-Dependent Apoptosis

For maximal oncogenic activity, cellular MYC protein levels need to be tightly controlled so that they do not induce apoptosis. Here, we show how ubiquitin ligase UBR5 functions as a molecular rheostat to prevent excess accumulation of MYC protein. UBR5 ubiquitinates MYC and its effects on MYC protein stability are independent of FBXW7. Silencing of endogenous UBR5 induced MYC protein expression and regulated MYC target genes. Consistent with the tumor suppressor function of UBR5 (HYD) in Drosophila, HYD suppressed dMYC-dependent overgrowth of wing imaginal discs. In contrast, in cancer cells, UBR5 suppressed MYC-dependent priming to therapy-induced apoptosis. Of direct cancer relevance, MYC and UBR5 genes were coamplified in MYC-driven human cancers. Functionally, UBR5 suppressed MYC-mediated apoptosis in p53-mutant breast cancer cells with UBR5/MYC coamplification. Furthermore, single-cell immunofluorescence analysis demonstrated reciprocal expression of UBR5 and MYC in human basal-type breast cancer tissues. In summary, UBR5 is a novel MYC ubiquitin ligase and an endogenous rheostat for MYC activity. In MYC-amplified, and p53-mutant breast cancer cells, UBR5 has an important role in suppressing MYC-mediated apoptosis priming and in protection from drug-induced apoptosis. SIGNIFICANCE: These findings identify UBR5 as a novel MYC regulator, the inactivation of which could be very important for understanding of MYC dysregulation on cancer cells. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/7/1414/F1.large.jpg.

Tumor-infiltrating lymphocytes and CD8+ T cells predict survival of triple-negative breast cancer

PURPOSE

Tumor inflammatory response was evaluated as a prognostic feature in triple-negative breast cancer (TNBC) and compared with the clinical prognosticators of breast cancer and selected biomarkers of cancer cell proliferation.

METHODS

TNBC patients (n = 179) with complete clinical data and up to 18-year follow-up were obtained from Auria biobank, Turku University Hospital, Turku, Finland. Tumor-infiltrating lymphocytes (TILs) and several subtypes of inflammatory cells detected with immunohistochemistry were evaluated in different tumor compartments in full tissue sections and tissue microarrays.

RESULTS

Deficiency of stromal TILs and low number of CD8⁺ T cells independently predicted mortality in TNBC (HR 2.4, p 0.02 and HR 2.1, p 0.02, respectively). Each 10% decrease in stromal TILs resulted in 20% increased risk of mortality. An average of 13.2-year survival difference was observed between the majority (> 75%) of patients with low (< 14% of TILs) vs high (≥ 14% of TILs) frequency of CD8⁺ T cells. The prognostic value of TILs and CD8⁺ T cells varied when evaluated in different tumor compartments. TILs and CD8⁺ T cells were significantly associated with Securin and Separase, essential regulators of metaphase-anaphase transition of the cell cycle.

DISCUSSION

TILs and CD8⁺ T cells provide additional prognostic value to the established clinical prognostic markers in TNBC. However, possible clinical applications would still benefit from systematic guidelines for evaluating tumor inflammatory response. Increasing understanding on the interactions between the regulation of cancer cell proliferation and inflammatory response may in future advance treatment of TNBC.

Proliferation-associated miRNAs-494, -205, -21 and -126 detected by in situ hybridization: expression and prognostic potential in breast carcinoma patients

PURPOSE

To visualize by in situ hybridization (ISH) the levels of a set of proliferation-associated miRNAs and to evaluate their impact and clinical applicability in prognostication of invasive breast carcinoma.

METHODS

Tissue specimen from breast carcinoma patients were investigated for miRNAs-494, -205, -21 and -126. Prognostic associations for levels of miRNAs were analyzed based on complete clinical data and up to 22.5-year follow-up of the patient material (n = 285). For detection of the miRNAs, an automated sensitive protocol applying in situ hybridization was developed.

RESULTS

MiRNA-494 indicated prognostic value for patients with invasive breast carcinoma. Among node-negative disease reduced level of miRNA-494 predicted 8.5-fold risk of breast cancer death (p = 0.04). Altered levels and expression patterns of the studied miRNAs were observed in breast carcinomas as compared to benign breast tissue.

CONCLUSIONS

The present paper reports for the first time on the prognostic value of miRNA-494 in invasive breast cancer. Particularly, detection of miRNA-494 could benefit patients with node-negative breast cancer in identifying subgroups with aggressive disease. Based on our experience, the developed automatic ISH method to visualize altered levels of miRNAs-494, -205, -21 and -126 could be applied to routine pathology diagnostics providing that conditions of tissue treatment, especially fixation delays, are managed.

PTTG1-interacting protein (PTTG1IP/PBF) predicts breast cancer survival

Background

PTTG1-interacting protein (PTTG1IP) is an oncogenic protein, which participates in metaphase-anaphase transition of the cell cycle through activation of securin (PTTG1). PTTG1IP promotes the shift of securin from the cell cytoplasm to the nucleus, allowing the interaction between separase and securin. PTTG1IP overexpression has been previously observed in malignant disease, e.g. in breast carcinoma. However, the prognostic value of PTTG1IP in breast carcinoma patients has not previously been revealed.

Methods

A total of 497 breast carcinoma patients with up to 22-year follow-up were analysed for PTTG1IP and securin immunoexpression. The results were evaluated for correlations with the clinical prognosticators and patient survival.

Results

In our material, negative PTTG1IP immunoexpression predicted a 1.5-fold risk of breast cancer death (p = 0.02). However, adding securin immunoexpression to the analysis indicated an even stronger and independent prognostic power in the patient material (HR = 2.5, p < 0.0001). The subcellular location of securin was found with potential prognostic value also among the triple-negative breast carcinomas (n = 96, p = 0.052).

Conclusions

PTTG1IP-negativity alone and in combination with high securin immunoexpression indicates a high risk of breast cancer death, resulting in up to 14-year survival difference in our material.

Low cdc27 and high securin expression predict short survival for breast cancer patients

Cell cycle regulators cdc27 and securin participate in control of the mitotic checkpoint and survey the mitotic spindle to maintain chromosomal integrity. This is achieved by their functions in metaphase-anaphase transition, DNA damage repair, enhancement of mitotic arrest and apoptosis. We report on the roles of cdc27 and securin in aneuploidy and prognosis of breast cancer. The study comprises 429 breast cancer patients with up to 22 years of follow-up. DNA content was determined by image cytometry, and immunopositivity for cdc27 and securin was based on tissue microarrays. An inverse association between cdc27 and securin expression was observed in both image cytometric and immunohistochemical analyses. Low cdc27 and high securin expression identified patients with significant difference in disease outcome. Cdc27 and securin immunoexpression identified patients at risk of early cancer death within five years from diagnosis. In multivariate analysis, the combination of cdc27 and securin immunohistochemistry was the strongest predictor of cancer death after lymph node status. We demonstrate, for the first time in human breast cancer, the prognostic value of cdc27 and securin immunohistochemistry. Cdc27 and securin appear promising biomarkers for applications in predicting disease progression, prognostication of individual patients and potential in anti-mitotic drug development.

Characterization of Diaphanous-related formin FMNL2 in human tissues

Background

Diaphanous-related formins govern actin-based processes involved in many cellular functions, such as cell movement and invasion. Possible connections to developmental processes and cellular changes associated with malignant phenotype make them interesting study targets. In spite of this, very little is known of the tissue distribution and cellular location of any mammalian formin. Here we have carried out a comprehensive analysis of the formin family member formin -like 2 (FMNL2) in human tissues.

Results

An FMNL2 antibody was raised and characterized. The affinity-purified FMNL2 antibody was validated by Western blotting, Northern blotting, a peptide competition assay and siRNA experiments. Bioinformatics-based mRNA profiling indicated that FMNL2 is widely expressed in human tissues. The highest mRNA levels were seen in central and peripheral nervous systems. Immunohistochemical analysis of 26 different human tissues showed that FMNL2 is widely expressed, in agreement with the mRNA profile. The widest expression was detected in the central nervous system, since both neurons and glial cells expressed FMNL2. Strong expression was also seen in many epithelia. However, the expression in different cell types was not ubiquitous. Many mesenchymal cell types showed weak immunoreactivity and cells lacking expression were seen in many tissues. The subcellular location of FMNL2 was cytoplasmic, and in some tissues a strong perinuclear dot was detected. In cultured cells FMNL2 showed mostly a cytoplasmic localization with perinuclear accumulation consistent with the Golgi apparatus. Furthermore, FMNL2 co-localized with F-actin to the tips of cellular protrusions in WM164 human melanoma cells. This finding is in line with FMNL2's proposed function in the formation of actin filaments in cellular protrusions, during amoeboid cellular migration.

Conclusion

FMNL2 is expressed in multiple human tissues, not only in the central nervous system. The expression is especially strong in gastrointestinal and mammary epithelia, lymphatic tissues, placenta, and in the reproductive tract. In cultured melanoma cells, FMNL2 co-localizes with F-actin dots at the tips of cellular protrusions.

Altered expression of p120catenin predicts poor outcome in invasive breast cancer

PURPOSE

The study focuses on p120catenin, a regulator of cell adhesion, which has previously been described in many malignancies and suggested with a role in invasion and metastatic behaviour. In this study, we investigate the role of altered immunoexpression of p120catenin isoforms in the prognosis of invasive breast cancer (n = 351).

METHODS

We used cDNA microarrays to screen differences in gene expression in invasive breast cancer in general, and between local and metastasized disease particularly. On this basis, we performed p120catenin immunohistochemistry in order to confirm the prognostic value of p120catenin isoforms on tissue microarrays comprising 341 patients from the era of mammographic screening, directed to modern surgical and oncological treatments, and followed-up for maximum of 20 years.

RESULTS

In cDNA microarray analysis, p120catenin was discovered down-regulated along with E-cadherin and alpha-catenin. In addition, p120catenin distinguished metastasized breast cancer from local disease. Immunohistochemistry confirmed the value of p120catenin as an independent prognosticator of breast cancer survival. In our results, p120catenin was associated with 3.7-fold risk of breast cancer death in multivariate Cox's regression analyses adjusted for the established prognosticators of breast cancer (p = 0.039). Particularly, the long isoform of p120catenin predicted metastatic disease (p = 0.029).

CONCLUSION

The present paper is the first report on p120catenin in invasive breast cancer based on a well-characterized patient material with long-term follow-up. We observed altered expression of p120catenin isoforms in invasive breast cancer and, in our material, the decrease in p120 immunoexpression was significantly associated with poor outcome of disease.

Mutations/polymorphisms in the 55 kDa subunit of DNA polymerase epsilon in human colorectal cancer

BACKGROUND

Defects of some DNA polymerases have shown associations with cancer, but data on DNA polymerase epsilon are limited. This study investigated mutations in the 55 kDa subunit gene of DNA polymerase epsilon in colorectal cancer.

MATERIALS AND METHODS

DNA from 16 human colorectal cancer and 9 control samples was studied with polymerase chain reaction-single-strand comformation polymorphism analysis and DNA sequencing.

RESULTS

DNA polymerase epsilon gene alterations were identified in 5 out of the 16 cases (31.2%). Two samples showed a T-C transition at exon 17 (potential tyrosine to histidine substitution), and an A-G transition at intron 7; one sample showed an A-G transition at intron 8. An AATT deletion was observed at intron 18 in 3 out of the 16 colon cancer cases (grades 2, 3, and 2, and Dukes' classes C, D, and C, respectively).

CONCLUSION

Because the AATT deletion has also been found in breast cancer, the region may be a mutation hot spot, possibly involved in the carcinogenetic path in advanced colorectal cancer.

Genomic changes of the 55 kDa subunit of DNA polymerase epsilon in human breast cancer

BACKGROUND

DNA polymerases (Pols) represent potential candidates for cancer genes because of their central functions in DNA metabolism. Defects of some DNA Pols have shown cancer associations, but data on DNA polymerase (Pol) epsilon is limited.

MATERIALS AND METHODS

Twenty-four human breast cancer DNA samples and four control DNA samples were examined for possible mutation in the entire coding region of the 55 kDa small subunit of the human DNA Pol epsilon gene using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of the DNA and sequence analysis. In addition, 20 control DNAs were studied with PCR-SSCP for the end of intron 18 and exon 19 region.

RESULTS

An AATT deletion was found at one location in intron 18 in 2 out of the 24 breast cancer cases (8%), but in none of the control cases. In addition, a single base transition was found in the cancer DNAs in intron 14, but the same changes were also found in the control DNAs, suggesting polymorphism.

CONCLUSION

Specific changes might occur in the 55 kDa small subunit DNA sequence of DNA Pol epsilon in breast cancer. The deletion at the region of intron-exon junction may not affect the protein code, but could potentially influence splicing efficiency and expression levels, possibly impairing the function of Pol epsilon DNA.

Zaspopathy in a large classic late-onset distal myopathy family

Distal myopathies have been associated with mutations in titin, dysferlin, GNE, desmin and myosin. Of these, only titin mutations were previously known to cause dominant late-onset distal myopathy. Recent findings, however, have indicated that patients affected with myofibrillar myopathy have a more distal than proximal muscle phenotype and a proportion of these may have mutations in myotilin, ZASP or filamin C, besides previously known desmin and alphaB-crystallin. Here we report that the disorder in one of the well-characterized autosomal dominant distal myopathy families, the Markesbery et al. family, first reported in 1974, is caused by ZASP mutation A165V. Previous linkage to the titin locus 2q31 proved incorrect. ZASP expression by immunoblotting shows normal presence of the main 32 and 78 kDa bands and immunohistochemistry in patients reveals normal Z-disc localization except for moderate accumulations together with myotilin, desmin alphaB-crystallin and alpha-actinin. Muscle imaging reveals involvement in both the posterior and anterior compartments of the lower leg and considerable affection of proximal leg muscles at later stages. Haplotype studies in this family and in five other unrelated families with European ancestry carrying the identical A165V mutation share common markers at the locus suggesting the existence of a founder mutation.

Biochemical and clinical approaches in evaluating the prognosis of colon cancer

BACKGROUND

Colorectal adenocarcinoma is a common malignant neoplasm in the Western world. To achieve optimal treatment results, the risk estimation of recurrence should be as accurate as possible.

MATERIALS AND METHODS

Tissue material from tumour and normal mucosa was taken from six patients and was analysed to screen aberrantly expressed genes using cDNA microarray. Selected up-regulated genes were chosen for further analysis by immunohistochemistry. For this purpose a tissue array material of 114 colorectal cancer patients was obtained. In addition to the routinely used proliferation marker Ki-67, the analysed proteins included securin and CDC25B.

RESULTS

Processes such as cellular defense, cell structure, motility and cell division were found to be notably represented among the most deregulated genes. A significant portion of the overexpressed genes included those functioning in the cell cycle. Immunohistochemical stainings of securin and CDC25B showed a consistent expression pattern with that of cDNA microarray analysis. There was no statistical association between the studied proliferation markers and survival. Instead, there was a significant association between the Dukes' class and the histological grade (p=0.04), but not between histological grade and survival. The survival of Dukes' B patients was significantly poorer if no regional lymph nodes were studied compared with the Dukes' B patients with even a single lymph node was studied (p=0.04, hazard ratio 2.7).

CONCLUSION

Tumour stage is superior in estimating the prognosis of patients with colonic cancer compared with the grading of cell cycle regulators or histological grade of the cancer. The study of regional lymph nodes is essential to identify the patients who would benefit from adjuvant chemotherapy.

Myotilinopathy in a family with late onset myopathy

Mutations in titin are well known cause of late onset autosomal dominant distal myopathy. Mutations in another sarcomeric protein, myotilin, were first identified in two families with dominant limb girdle muscular phenotype. Recently, however, myotilin mutations have been associated with more distal phenotypes in patients with late onset myofibrillar myopathy. We report here a multigenerational French family in which gene sequencing identified a S60F myotilin mutation in all patients with full penetrance despite very late onset. The family was originally reported as a distal myopathy but intrafamilial variability was remarkable with proximal or distal muscle weakness or both. Extended morphological characteristics of muscle biopsy findings in myotilinopathy indicate that immunohistochemistry may be important for selection of molecular genetic approach in myofibrillar myopathy.

mRNA differential display of gene expression in colonic carcinoma

We analyzed changes in gene expression in human colonic carcinoma by fluorescent mRNA differential display. RNA isolated from two samples of normal colon and four cases of colonic adenocarcinoma were amplified with a 15 x 32 set of primers resulting in 2880 cDNAs analyzed with an automated sequencer. Electrophoretic patterns implying constitutive gene expression as well as upregulated and downregulated expression in carcinomas were identified. Forty such cDNA fragments were purified by a novel fluorescent polyacrylamide gel electrophoresis (PAGE)-based method and identified by cyclic sequencing. Most genes showing differential expression were upregulated in colonic carcinoma. Upregulated genes included those for various ribosomal and mitochondrial proteins, heat shock proteins, nucleolar RNA-helicase and phosphoserine aminotransferase. Downregulated genes included histone H3.3. In conclusion, genes associated with vital cellular functions such as transcription, protein synthesis and mitochondrial metabolism were upregulated in colonic carcinoma. Fluorescent mRNA differential display can be applied to the identification of novel cancer-related genes for diagnostic, prognostic and therapeutic purposes.

Baseline diene conjugation in LDL lipids as a direct measure of in vivo LDL oxidation

OBJECTIVES

To additionally test validity of the recently developed method (LDL baseline diene conjugation, LDL-BDC) for determination of circulating oxidized LDL.

DESIGN AND METHODS

A detailed comparison between the ultracentrifugation and heparin precipitation methods for LDL isolation was performed to test suitability of the fast precipitation method. Validity of LDL-BDC as an indicator of circulating oxidized LDL was tested by comparing LDL-BDC to results obtained by the immunological autoantibody method.

RESULTS

BDC values in LDL isolated by heparin precipitation did not differ from those isolated by sequential ultracentrifugation. While highest amount of diene conjugation was found in LDL (40% of that in serum), substantial amounts were also found in VLDL (31%) and HDL (25%). When analyzed in the same samples, assays for the titer of autoantibodies against oxidized LDL and LDL-BDC were found to show good correlation (r = 0.57, p = 0.001, n = 29).

CONCLUSIONS

These results, together with thus far conducted studies on clinical applicability of the method, indicate that LDL-BDC is a promising candidate in search for a method for estimation of LDL oxidation in vivo.