Differential expression of genes involved in the epigenetic regulation of cell identity in normal human mammary cell commitment and differentiation

The establishment and maintenance of mammary epithelial cell identity depends on the activity of a group of proteins, collectively called maintenance proteins, that act as epigenetic regulators of gene transcription through DNA methylation, histone modification, and chromatin remodeling. Increasing evidence indicates that dysregulation of these crucial proteins may disrupt epithelial cell integrity and trigger breast tumor initiation. Therefore, we explored in silico the expression pattern of a panel of 369 genes known to be involved in the establishment and maintenance of epithelial cell identity and mammary gland remodeling in cell subpopulations isolated from normal human mammary tissue and selectively enriched in their content of bipotent progenitors, committed luminal progenitors, and differentiated myoepithelial or differentiated luminal cells. The results indicated that, compared to bipotent cells, differentiated myoepithelial and luminal subpopulations were both characterized by the differential expression of 4 genes involved in cell identity maintenance: CBX6 and PCGF2, encoding proteins belonging to the Polycomb group, and SMARCD3 and SMARCE1, encoding proteins belonging to the Trithorax group. In addition to these common genes, the myoepithelial phenotype was associated with the differential expression of HDAC1, which encodes histone deacetylase 1, whereas the luminal phenotype was associated with the differential expression of SMARCA4 and HAT1, which encode a Trithorax protein and histone acetylase 1, respectively. The luminal compartment was further characterized by the overexpression of ALDH1A3 and GATA3, and the down-regulation of NOTCH4 and CCNB1, with the latter suggesting a block in cell cycle progression at the G2 phase. In contrast, myoepithelial differentiation was associated with the overexpression of MYC and the down-regulation of CCNE1, with the latter suggesting a block in cell cycle progression at the G1 phase.

Systematic review of ablative therapy for the treatment of renal allograft neoplasms

BACKGROUND To date,there are no guidelines on the treatment of solid neoplasms in the transplanted kidney.Historically,allograft nephrectomy has been considered the only reasonable option.More recently,nephron-sparing surgery (NSS) and ablative therapy (AT) have been proposed as alternative procedures in selected cases.AIM To review outcomes of AT for the treatment of renal allograft tumours.METHODS We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 Checklist.PubMed was searched in March 2019 without time restrictions for all papers reporting on radiofrequency ablation (RFA),cryoablation (CA),microwave ablation (MWA),high-intensity focused ultrasound (HIFU),and irreversible electroporation (IRE) of solid tumours of the kidney allograft.Only original manuscripts describing actual cases and edited in English were considered.All relevant articles were accessed in full text.Additional searches included all pertinent references.Selected studies were also assessed for methodological quality using a tool based on a modification of the Newcastle Ottawa scale.Data on recipient characteristics,transplant characteristics,disease characteristics,treatment protocols,and treatment outcomes were extracted and analysed.Given the nature and the quality of the studies available (mostly retrospective case reports and small retrospective uncontrolled case series),a descriptive summary was provided.RESULTS Twenty-eight relevant studies were selected describing a total of 100 AT procedures in 92 patients.Recipient age at diagnosis ranged from 21 to 71 years whereas time from transplant to diagnosis ranged from 0.1 to 312 mo.Most of the neoplasms were asymptomatic and diagnosed incidentally during imaging carried out for screening purposes or for other clinical reasons.Preferred diagnostic modality was Doppler-ultrasound scan followed by computed tomography scan,and magnetic resonance imaging.Main tumour types were: papillary renal cell carcinoma (RCC) and clear cell RCC.Maximal tumour diameter ranged from 5 to 55 mm.The vast majority of neoplasms were T1a N0 M0 with only 2 lesions staged T1b N0 M0.Neoplasms were managed by RFA (n = 78),CA (n = 15),MWA (n = 3),HIFU (n = 3),and IRE (n = 1).Overall,3 episodes of primary treatment failure were reported.A single case of recurrence was identified.Follow-up ranged from 1 to 81 mo.No cancer-related deaths were observed.Complication rate was extremely low (mostly < 10%).Graft function remained stable in the majority of recipients.Due to the limited sample size,no clear benefit of a single procedure over the other ones could be demonstrated.CONCLUSION AT for renal allograft neoplasms represents a promising alternative to radical nephrectomy and NSS in carefully selected patients.Properly designed clinical trials are needed to validate this therapeutic approach.

Epithelial cell identity in hyperplastic precursors of breast cancer

Introduction:In the adult human breast,hyperplastic enlarged lobular unit(HELU) and atypical ductal hyperplasia(ADH) are two common abnormalities that frequently coexist with ductal carcinoma in situ(DCIS).For this reason,they have been proposed as the early steps in a biological continuum toward breast cancer.Methods:We investigated in silico the expression of 369 genes experimentally recognized as involved in establishing and maintaining epithelial cell identity and mammary gland remodeling,in HELUs or ADHs with respect to the corresponding patient-matched normal tissue.Results:Despite the common luminal origin,HELUs and ADHs proved to be characterized by distinct gene profiles that overlap for 5 genes only.While HELUs were associated with the overexpression of progesterone receptor(PGR),ADHs were characterized by the overexpression of estrogen receptor 1(ESR1) coupled with the overexpression of some proliferation-associated genes.Conclusions:This unexpected finding contradicts the notion that in differentiated luminal cells the expression of estrogen receptor(ER) is dissociated from cell proliferation and suggests that the establishing of an ER-dependent signaling is able to sustain cell proliferation in an autocrine manner as an early event in tumor initiation.Although clinical evidence indicates that only a fraction of HELUs and ADHs evolve to invasive cancer,present findings warn that exposure to synthetic progestins,frequently administered as hormone-replacement therapy,and estrogens,when abnormally produced by adipose cells and persistently present in the stroma surrounding the mammary gland,may cause these hyperplastic lesions.

Incidence, risk factors, and outcome of BK polyomavirus infection after kidney transplantation

BACKGROUND Polyomavirus-associated nephropathy is a leading cause of kidney allograft failure. Therapeutic options are limited and prompt reduction of the net state of immunosuppression represents the mainstay of treatment. More recent application of aggressive screening and management protocols for BK-virus infection after renal transplantation has shown encouraging results. Nevertheless,long-term outcome for patients with BK-viremia and nephropathy remains obscure. Risk factors for BK-virus infection are also unclear.AIM To investigate incidence, risk factors, and outcome of BK-virus infection after kidney transplantation.METHODS This single-centre observational study with a median follow up of 57(31-80) mo comprises 629 consecutive adult patients who underwent kidney transplantation between 2007 and 2013. Data were prospectively recorded and annually reviewed until 2016. Recipients were periodically screened for BK-virus by plasmaquantitative polymerized chain reaction. Patients with BK viral load ≥ 1000 copies/mL were diagnosed BK-viremia and underwent histological assessment to rule out nephropathy. In case of BK-viremia, immunosuppression was minimized according to a prespecified protocol. The following outcomes were evaluated: patient survival, overall graft survival, graft failure considering death as a competing risk, 30-d-event-censored graft failure, response to treatment,rejection, renal function, urologic complications, opportunistic infections, newonset diabetes after transplantation, and malignancies. We used a multivariable model to analyse risk factors for BK-viremia and nephropathy.RESULTS BK-viremia was detected in 9.5% recipients. Initial viral load was high(≥ 10000 copies/mL) in 66.7% and low(< 10000 copies/mL) in 33.3% of these patients.Polyomavirus-associated nephropathy was diagnosed in 6.5% of the study population. Patients with high initial viral load were more likely to experience sustained viremia(95% vs 25%, P < 0.00001), nephropathy(92.5% vs 15%, P <0.00001), and polyomavirus-related graft loss(27.5% vs 0%, P = 0.0108) than recipients with low initial viral load. Comparison between recipients with or without BK-viremia showed that the proportion of patients with Afro-Caribbean ethnicity(33.3% vs 16.5%, P = 0.0024), panel-reactive antibody ≥ 50%(30% vs14.6%, P = 0.0047), human leukocyte antigen(HLA) mismatching > 4(26.7% vs13.4%, P = 0.0110), and rejection within thirty days of transplant(21.7% vs 9.5%; P= 0.0073) was higher in the viremic group. Five-year patient and overall graft survival rates for patients with or without BK-viremia were similar. However,viremic recipients showed higher 5-year crude cumulative(22.5% vs 12.2%, P =0.0270) and 30-d-event-censored(22.5% vs 7.1%, P = 0.001) incidences of graft failure than control. In the viremic group we also observed higher proportions of recipients with 5-year estimated glomerular filtration rate < 30 mL/min than the group without viremia: 45% vs 27%(P = 0.0064). Urologic complications were comparable between the two groups. Response to treatment was complete in55%, partial in 26.7%, and absent in 18.3% patients. The nephropathy group showed higher 5-year crude cumulative and 30-d-event-censored incidences of graft failure than control: 29.1% vs 12.1%(P = 0.008) and 29.1% vs 7.2%(P <0.001), respectively. Our multivariable model demonstrated that Afro-Caribbean ethnicity, panel-reactive antibody > 50%, HLA mismatching > 4, and rejection were independent risk factors for BK-virus viremia whereas cytomegalovirus prophylaxis was protective.CONCLUSION Current treatment of BK-virus infection offers sub-optimal results. Initial viremia is a valuable parameter to detect patients at increased risk of nephropathy. Panelreactive antibody > 50% and Afro-Caribbean ethnicity are independent predictors of BK-virus infection whereas cytomegalovirus prophylaxis has a protective effect.

Significance of ipsilateral breast tumor recurrence after breast conserving treatment: role of surgical removal

Objective： To analyze the pattern over time （dynamics） of further recurrence and death after ipsilateral breast tumor recurrence （IBTR） in breast cancer patients undergoing breast conserving treatment （BCT）. Methods： A total of 338 evaluable patients experiencing IBTR were extracted from a database of 3,293 patients undergoing BCT. The hazard rates for recurrence and mortality throughout 10 years of follow-up after IBTR were assessed and were compared to the analogous estimates associated to the primary treatment. Results： In a time frame with the time origin at the surgical treatment for IBTR, the hazard rate for further recurrence displays a bimodal pattern （peaks at the second and at the sixth year）. Patients receiving mastectomy for IBTR reveal recurrence and mortality dynamics similar to that of node positive （N＋） patients receiving mastectomy as primary surgery, apart from the first two-three years, when IBTR patients do worse. If the patients with time to IBTR longer than 2.5 years are considered, differences disappear. Conclusions： The recurrence and mortality dynamics following IBTR surgical removal is similar to the corresponding dynamics following primary tumor removal. In particular, patients with time to IBTR in excess of 2.5 years behave like N＋ patients following primary tumor removal. Findings may be suitably explained by assuming that the surgical manoeuvre required by IBTR treatment is able to activate a sudden growing phase for tumor foci most of which, as suggested by the systemic model of breast cancer, would have reached the clinical level according to their own dynamics.

Differential Expression of Genes Involved in Cell Polarity, EMT and Cell-Fate in Breast Cancer and Corresponding Normal Tissue

Objectives: Cell polarity and epithelial morphology are peculiar features of cells forming the terminal ductal lobular unit, and they are early lost during neoplastic transformation because of an epithelial-mesenchymal transition (EMT). To understand these early events we analyzed a set of 125 genes related to cell polarity, EMT and cell-fate decision in 26 breast cancer specimens and corresponding patient-matched normal tissue. Methods: The difference of gene expression was explored by t-paired test. In addition, to evidence latent variables accounting for genes correlations, a Factor Analysis was applied as exploratory technique. Results: Among the 90 differentially expressed genes, those coding for cell polarity complexes, apical-junctional components and luminal cytokeratins were overexpressed in tumor samples (suggesting a terminally differentiated phenotype) whereas those coding for stemness-associated features or related with EMT were expressed in normal tissues but not in tumor samples, suggesting the persistence of stem/progenitor cells. Factor analysis confirmed these findings and indicated that the difference between tumors and normal tissues can be synthesized in three main features representative of specific molecular/morphological alterations. Conclusions: The a priori definition of a selected panel of genes and the application of an exploratory statistical approach, greatly contribute to reduce the intrinsic biological complexity of tumor specimens and to describe the difference between tumor specimens and corresponding histologically normal tissues.