Long-term efficacy and safety of exemestane in the treatment of breast cancer

Exemestane, a steroidal aromatase inhibitor, is licensed for postmenopausal patients with estrogen receptor (ER)-positive breast cancer as second-line therapy in metastatic disease following antiestrogen failure and as part of sequential adjuvant therapy following initial tamoxifen. This study is a systematic literature review, evaluating exemestane in different clinical settings. The Ovid Medline (1948-2012), Embase (1980-2012), and Web of Science (1899-2012) databases were searched. Forty-two relevant articles covering randomized controlled trials were reviewed for efficacy and safety, and three for adherence. With regard to efficacy in metastatic disease, exemestane is superior to megestrol acetate after progression on tamoxifen. There is evidence for noninferiority to fulvestrant (following a prior aromatase inhibitor) and to nonsteroidal aromatase inhibitors in the first-line setting. Combined use with everolimus is shown to be more efficacious than exemestane alone following previous aromatase inhibitor use. In the adjuvant setting, a switch to exemestane after 2-3 years of tamoxifen is superior to 5 years of tamoxifen. Exemestane is noninferior to 5 years of tamoxifen as upfront therapy, and may have a role as an extended adjuvant therapy. Used as neoadjuvant therapy, increased breast conservation is achievable. As chemoprevention, exemestane significantly reduces the incidence of breast cancer in "at-risk" postmenopausal women. Exemestane is associated with myalgias and arthralgias, as well as reduced bone mineral density and increased risk of fracture, which do not appear to persist at follow-up, with subsequent return to pretreatment values. Compared with tamoxifen, there is a reduced incidence of endometrial changes, thromboembolic events, and hot flashes. Limited evidence shows nonadherence in 23%-32% of patients. Evidence is growing in support of exemestane in all clinical settings. It is generally more efficacious and has a better safety profile than tamoxifen. How it compares with the nonsteroidal aromatase inhibitors remains to be established. Further studies are required on adherence to ensure that maximum benefit is obtained.

Thyrocyte-specific inactivation of p53 and Pten results in anaplastic thyroid carcinomas faithfully recapitulating human tumors

Anaplastic thyroid carcinoma (ATC) is the most aggressive form of thyroid cancer, and often derives from pre-existing well-differentiated tumors. Despite a relatively low prevalence, it accounts for a disproportionate number of thyroid cancer-related deaths, due to its resistance to any therapeutic approach. Here we describe the first mouse model of ATC, obtained by combining in the mouse thyroid follicular cells two molecular hallmarks of human ATC: activation of PI3K (via Pten deletion) and inactivation of p53. By 9 months of age, over 75% of the compound mutant mice develop aggressive, undifferentiated thyroid tumors that evolve from pre-existing follicular hyperplasia and carcinoma. These tumors display all the features of their human counterpart, including pleomorphism, epithelial-mesenchymal transition, aneuploidy, local invasion, and distant metastases. Expression profiling of the murine ATCs reveals a significant overlap with genes found deregulated in human ATC, including genes involved in mitosis control. Furthermore, similar to the human tumors, [Pten, p53]thyr-/- tumors and cells are highly glycolytic and remarkably sensitive to glycolysis inhibitors, which synergize with standard chemotherapy. Taken together, our results show that combined PI3K activation and p53 loss faithfully reproduce the development of thyroid anaplastic carcinomas, and provide a compelling rationale for targeting glycolysis to increase chemotherapy response in ATC patients.

A comparative study of cell cycle mediator protein expression patterns in anaplastic and papillary thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is an extremely aggressive and rapidly fatal neoplasm. The aim of this study was to identify a limited cell cycle associated protein expression pattern unique to ATC and to correlate that pattern with clinical outcome. This represents one of the largest tissue micro-array projects comparing the cell cycle protein expression data of ATC to other well-differentiated tumors in the literature. Tissue microarrays were created from 21 patients with ATC and an age and gender matched cohort of patients with papillary thyroid carcinoma (PTC). Expression of epidermal growth factor receptor, cyclin D1, cyclin E, p53, p21, p16, aurora kinase A, opioid growth factor (OGF), OGF-receptor, thyroglobulin and Ki-67 was evaluated in a semi-quantitative fashion. Differences in protein expression between the cohorts were evaluated using chi-square tests with Bonferroni adjustments. Survival time and presence of metastasis at presentation were collected. The ATC cohort showed a statistically significant decrease (p < 0.05) in thyroglobulin expression and statistically significant increases (p < 0.05) in Ki-67 and p53 expression as compared with the PTC cohort. A trend toward loss of p16 and p21 expression was noted in the ATC cohort. A trend toward decreased survival was noted with p21 expression. These data indicate disruption of the normal cell cycle with aberrant expression of multiple protein markers suggesting increased proliferative activity and loss of control of cell cycle progression to G₁ phase. These findings support the assertion that ATC may represent the furthest end of a continuum of thyroid carcinoma dedifferentiation.

Prognostic factors and treatment outcomes of 100 cases of anaplastic thyroid carcinoma

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is a malignancy with one of the highest fatality rates. Here we report a retrospective study of the treatment and other factors associated with its outcomes.

MATERIALS AND METHODS

The medical records of 100 patients diagnosed with ATC at Ito Hospital between 1993 and 2009 were reviewed and pertinent information was extracted and analyzed.

RESULTS

There were 80 women and 20 men, and their median age at diagnosis was 68 years (range, 41-90 years). Thirteen patients had a history of well-differentiated thyroid carcinoma. Six patients had a small ATC focus within a differentiated carcinoma. All cases were retrospectively staged according to the Union for International Cancer Control classification system, and the results were stage IVA in 11 cases, stage IVB in 31 cases, and stage IVC in 58 cases. Seventy patients underwent surgical treatment, and complete resection was performed in 24 of them. Seventy-eight patients received radiotherapy, and 58 of them received a total dose of ≥40 Gy. Twenty-seven patients received chemotherapy. Only 15 patients received multimodal therapy (surgery, radiotherapy, and chemotherapy). The 1-year survival rates according to stage were as follows: stage IVA, 72.7%; stage IVB, 24.8%; and stage IVC, 8.2%. Multivariate analysis identified age ≥70 years, white blood cell ≥10,000 mm(3), extrathyroidal invasion, and distant metastasis at the time of diagnosis as prognostic factors. Survival after complete resection was significantly better than after incomplete resection or no resection. The results also suggested that radiation doses of ≥40 Gy were associated with significantly longer survival.

CONCLUSION

Although the prognosis of most patients with ATC continues to be poor, surgery, radiotherapy, and a combination of both improved the survival of patients with ATC.

Dedifferentiation of differentiated thyroid carcinoma cell line FTC-133 is enhanced by 131I pretreatment

INTRODUCTION

Differentiated thyroid carcinoma (DTC) usually has a high iodine uptake. However, dedifferentiation of DTC with decreased or no radioiodine ((131)I) uptake is observed in clinical practice, with poor prognosis. The aim of this study was to investigate the effects of (131)I radiation on radioiodine uptake (RAIU) and the expression of thyroid-specific molecules.

METHODS

FTC-133 cells were treated with (131)I, the dosage dictated by methylthiazol tetrazolium test results and preliminary experiments. The experimental cell group was incubated with (131)I for 48 h and then cultured for 3 months in (131)I-free medium. The control group was set without (131)I. Primary cells were defined as the blank group. Following treatment, RAIU was measured with a gamma counter as the counts/cell number. Na(+)/I(-) symporter (NIS), thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase (TPO) and thyroglobulin (Tg) levels were detected by Western blotting and radioimmunoassay, and their mRNAs were detected by real-time polymerase chain reaction.

RESULTS

RAIU of FTC-133 cells decreased gradually after coincubation with (131)I and did not recover even if (131)I was removed. The relative RAIU of the control and experimental groups was 0.567 and 0.182, respectively, a statistically significant difference (P<.01). Expression of NIS, TSHR, TPO and Tg decreased in the experimental group to a statistically significant degree compared to that of controls (P<.05).

CONCLUSION

Changes in the mRNA levels were in accordance with the expression of thyroid-specific proteins. Thus, FTC-133 cells undergo dedifferentiation during long-term culture in vitro, and (131)I may promote this progress.

Molecular pathogenesis of follicular cell derived thyroid cancers

Thyroid cancers are the most common endocrine malignancy. Radiation exposure, family history of thyroid cancer and some inherited conditions are the most important predisposing factors for the development of thyroid cancer. Three mitogenic signalling pathways have been described in the thyroid cell, which are influenced by various stimulatory and inhibitory hormones, growth factors and neurotransmitters. Various proto-oncogenes and oncogenes like ras, braf, trk, met and RET also play a role in the signal transduction systems. Two theories have been described in thyroid cancer pathogenesis, the foetal cell carcinogenesis theory and the more common, multistep carcinogenesis theory. The multistep carcinogenesis theory is now the accepted model in many human cancers, including thyroid cancer. The early events of tumour formation are the consequence of activation of either various growth factors or the proto-oncogenes like ras, met or ret. This results in the formation of differentiated thyroid cancers like the papillary, follicular or Hurthle cell cancers. The later stages of tumour formation involve further activation of proto-oncogenes and loss or inactivation of tumour suppressor genes like p53. Based on this theory, follicular carcinomas are generated from follicular adenomas and papillary carcinomas from precursor cells generated from thyrocytes. Anaplastic carcinoma may develop from papillary or follicular carcinoma by dedifferentiation. In this review article, we highlight the molecular pathogenesis of thyroid tumours.

Gene expression profiling associated with the progression to poorly differentiated thyroid carcinomas

BACKGROUND

Poorly differentiated thyroid carcinomas (PDTC) represent a heterogeneous, aggressive entity, presenting features that suggest a progression from well-differentiated carcinomas. To elucidate the mechanisms underlying such progression and identify novel therapeutic targets, we assessed the genome-wide expression in normal and tumour thyroid tissues.

METHODS

Microarray analyses of 24 thyroid carcinomas - 7 classic papillary, 8 follicular variants of papillary (fvPTC), 4 follicular (FTC) and 5 PDTC - were performed and correlated with RAS, BRAF, RET/PTC and PAX8-PPARG alterations. Selected genes were validated by quantitative RT-PCR in an independent set of 28 thyroid tumours.

RESULTS

Unsupervised analyses showed that gene expression similarity was higher between PDTC and fvPTC, particularly for tumours harbouring RAS mutations. Poorly differentiated thyroid carcinomas presented molecular signatures related to cell proliferation, poor prognosis, spindle assembly checkpoint and cell adhesion. Compared with normal tissues, PTC had 307 out of 494 (60%) genes over-expressed, FTC had 137 out of 171 (80%) genes under-expressed, whereas PDTC had 92 out of 107 (86%) genes under-expressed, suggesting that gene downregulation is involved in tumour dedifferentiation. Significant UHRF1 and ITIH5 deregulated gene expression in PDTC, relatively to normal tissues, was confirmed by quantitative RT-PCR.

CONCLUSION

Our findings suggest that fvPTC are possible precursors of PDTC. Furthermore, UHRF1 and ITIH5 have a potential therapeutic/prognostic value for aggressive thyroid tumours.

Molecular alterations in hereditary and sporadic thyroid and parathyroid diseases

Thyroid and parathyroid diseases are fairly common and can be either hereditary or sporadic in nature. Tumors and tumor-like processes account for the majority of surgical pathology specimens in both of these endocrine organs. Molecular alterations are well known to occur in both the hereditary and the sporadic settings, and include alterations in tumor suppressor genes and oncogenes. The genetic pathways of tumors of parathyroid and thyroid are beginning to be well understood and are proving to be useful diagnostic, prognostic, and potential therapeutic targets. The molecular alterations in parathyroid and thyroid tumors and tumor-like processes are reviewed, with a focus on the potentially clinically useful diagnostic markers.

Geographical mapping of a multifocal thyroid tumour using genetic alteration analysis & miRNA profiling

Background

Papillary thyroid carcinoma (PTC) frequently presents as multiple tumour-foci within a single thyroid gland or pluriform, with synchronous tumours comprising different histological variants, raising questions regarding its clonality. Among the genetic aberrations described in PTC, the BRAF V600E mutation and ret/PTC activation occur most commonly. Several studies have investigated the genetic alteration status of multifocal thyroid tumours, with discordant results.

To address the question of clonality this study examined disparate geographical and morphological areas from a single PTC (classic PTC, insular and anaplastic foci, and tumour cells adjacent to vascular invasion and lymphocytic infiltrate) for the presence of ret/PTC 1 or BRAF mutations. Moreover, we wanted to investigate the consistency of miRNA signatures within disparate areas of a tumour, and geographical data was further correlated with expression profiles of 330 different miRNAs. Putative miRNA gene targets were predicted for differentially regulated miRNAs and immunohistochemistry was performed on tissue sections in an effort to investigate phenotypic variations in microvascular density (MVD), and cytokeratin and p53 protein expression levels.

Results

All of the morphological areas proved negative for ret/PTC 1 rearrangement. Two distinct foci with classic morphology harboured the BRAF mutation. All other regions, including the insular and anaplastic areas were negative for the mutation.

MiRNA profiles were found to distinguish tumours containing the BRAF mutation from the other tumour types, and to differentiate between the more aggressive insular & anaplastic tumours, and the classic variant. Our data corroborated miRNAs previously discovered in this carcinoma, and additional miRNAs linked to various processes involved in tumour growth and proliferation.

Conclusion

The initial genetic alteration analysis indicated that pluriform PTC did not necessarily evolve from classic PTC progenitor foci. Analysis of miRNA profiles however provided an interesting variation on the clonality question. While hierarchical clustering analysis of miRNA expression supported the hypothesis that discrete areas did not evolve from clonal expansion of tumour cells, it did not exclude the possibility of independent mutational events suggesting both phenomena might occur simultaneously within a tumour to enhance cancer progression in geographical micro-environments within a tumour.

Molecular Therapy in Urologic Oncology

During recent years, significant advances have been made in the field of molecular therapy in urologic oncology, mainly for advanced renal cell carcinoma. In this hitherto largely treatment-refractory disease, several agents have been developed targeting the von Hippel-Lindau metabolic pathway which is involved in carcinogenesis and progression of the majority of renal cell carcinomas. Although cure may not be expected, new drugs, such as the multikinase inhibitors sorafenib and sunitinib and the mammalian target of rapamycine inhibitor temsirolimus, frequently stabilize the disease course and may improve survival. Fewer data are available supporting molecular therapies in prostate, bladder, and testicular cancers. Preliminary data suggest a potential role of high-dose calcitriol and thalidomide in hormone-refractory prostate cancer, whereas targeted therapies in bladder and testicular cancers are still more or less limited to single-case experiences. The great theoretical potential and the multitude of possible targets and drug combinations, however, support further research into this exciting field of medical treatment of urologic malignancies.

Isolation and characterization of Pseudomonas aeruginosa PAO mutant that produces altered elastase

Triple-negative breast cancer (TNBC) is cancer that tested as negative for estrogen receptors (ER), progesterone receptors (PR), and excess human epidermal growth factor receptor 2 (HER2) protein which accounts for 15%–20% of all breast cancer cases. TNBC is considered to be a poorer prognosis than other types of breast cancer, mainly because it involves more aggressive phenotypes that are similar to stem cell–like cancer cells (cancer stem cell, CSC). Thus, targeted treatment of TNBC remains a major challenge in clinical practice. This review article surveys the latest evidence concerning the role of genomic alteration in current TNBC treatment responses, current clinical trials and potential targeting sites, CSC and drug resistance, and potential strategies targeting CSCs in TNBC. Furthermore, the role of insulin-like growth factor 1 receptor (IGF-1R) and nicotinic acetylcholine receptors (nAChR) in stemness expression, chemoresistance, and metastasis in TNBC and their relevance to potential treatments are also discussed and highlighted.