RESUMO
In triple-negative breast cancer (TNBC), the pleiotropic NDRG1 (N-Myc downstream regulated gene 1) promotes progression and worse survival, yet contradictory results were documented, and the mechanisms remain unknown. Phosphorylation and localization could drive NDRG1 pleiotropy, nonetheless, their role in TNBC progression and clinical outcome was not investigated. We found enhanced p-NDRG1 (Thr346) by TGFß1 and explored whether it drives NDRG1 pleiotropy and TNBC progression. In tissue microarrays of 81 TNBC patients, we identified that staining and localization of NDRG1 and p-NDRG1 (Thr346) are biomarkers and risk factors associated with shorter overall survival. We found that TGFß1 leads NDRG1, downstream of GSK3ß, and upstream of NF-κB, to differentially regulate migration, invasion, epithelial-mesenchymal transition, tumor initiation, and maintenance of different populations of cancer stem cells (CSCs), depending on the progression stage of tumor cells, and the combination of TGFß and GSK3ß inhibitors impaired CSCs. The present study revealed the striking importance to assess both total NDRG1 and p-NDRG1 (Thr346) positiveness and subcellular localization to evaluate patient prognosis and their stratification. NDRG1 pleiotropy is driven by TGFß to differentially promote metastasis and/or maintenance of CSCs at different stages of tumor progression, which could be abrogated by the inhibition of TGFß and GSK3ß.
Assuntos
Proteínas de Ciclo Celular , Peptídeos e Proteínas de Sinalização Intracelular , Fator de Crescimento Transformador beta , Neoplasias de Mama Triplo Negativas , Humanos , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/genética , NF-kappa B/genética , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismoRESUMO
The aim of the study was to stratify high-grade T1 (HGT1) bladder urothelial carcinoma into risk categories based on the presence of variant histology when compared to conventional urothelial carcinoma. The clinicopathological features of 104 HGT1 cases of urothelial carcinoma of the bladder with variant histology present in 34 (37%) were assessed. The endpoint of the study was disease-free survival and cancer-specific survival. Overall, variant histology was identified as a significant predictor of disease-free survival (P = 0.035). The presence of any specific variant histology (squamous, glandular, micropapillary, nested, microcystic, inverted growth, villous-like, basaloid, and lymphoepithelioma-like) was identified as a significant predictor of disease-free survival (P = 0.008) and cancer-specific survival (P = 0.0001) in HGT1 bladder cancer. Therefore, our results support including micropapillary HGT1 urothelial carcinoma within the aggressive high-risk category, as suggested by some recent clinical guidelines, but also favor nested, glandular, and basaloid to be placed in the high-risk category due to their potential of aggressive, life-threatening behavior and their limited response to bacillus Calmette-Guerin therapy. Conversely, the low-risk category would include urothelial carcinomas with squamous, inverted growth, or microcystic morphology, all with limited life-threatening potential and good response to current therapy. A very low-risk category would finally include patients whose tumors present villous-like or lymphoepithelioma-like morphology. In conclusion, our findings support the value of reporting the variant histology as a feature of variable aggressiveness in HGT1 urothelial carcinoma of the bladder.
Assuntos
Carcinoma Papilar , Carcinoma de Células Escamosas , Carcinoma de Células de Transição , Neoplasias da Bexiga Urinária , Carcinoma Papilar/patologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células de Transição/patologia , Feminino , Humanos , Masculino , Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/patologiaRESUMO
Purpose: On the basis of the identified stress-independent cellular functions of activating transcription factor 4 (ATF4), we reported enhanced ATF4 levels in MCF10A cells treated with TGFß1. ATF4 is overexpressed in patients with triple-negative breast cancer (TNBC), but its impact on patient survival and the underlying mechanisms remain unknown. We aimed to determine ATF4 effects on patients with breast cancer survival and TNBC aggressiveness, and the relationships between TGFß and ATF4. Defining the signaling pathways may help us identify a cell signaling-tailored gene signature.Experimental Design: Patient survival data were determined by Kaplan-Meier analysis. Relationship between TGFß and ATF4, their effects on aggressiveness (tumor proliferation, metastasis, and stemness), and the underlying pathways were analyzed in three TNBC cell lines and in vivo using patient-derived xenografts (PDX).Results: ATF4 overexpression correlated with TNBC patient survival decrease and a SMAD-dependent crosstalk between ATF4 and TGFß was identified. ATF4 expression inhibition reduced migration, invasiveness, mammosphere-forming efficiency, proliferation, epithelial-mesenchymal transition, and antiapoptotic and stemness marker levels. In PDX models, ATF4 silencing decreased metastases, tumor growth, and relapse after chemotherapy. ATF4 was shown to be active downstream of SMAD2/3/4 and mTORC2, regulating TGFß/SMAD and mTOR/RAC1-RHOA pathways independently of stress. We defined an eight-gene signature with prognostic potential, altered in 45% of 2,509 patients with breast cancer.Conclusions: ATF4 may represent a valuable prognostic biomarker and therapeutic target in patients with TNBC, and we identified a cell signaling pathway-based gene signature that may contribute to the development of combinatorial targeted therapies for breast cancer. Clin Cancer Res; 24(22); 5697-709. ©2018 AACR.
Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Transdução de Sinais , Proteínas Smad/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Fator 4 Ativador da Transcrição/genética , Animais , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Biologia Computacional/métodos , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Xenoenxertos , Humanos , Imuno-Histoquímica , Camundongos , Modelos Biológicos , Prognóstico , RNA Interferente Pequeno/genética , Transcriptoma , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/mortalidadeRESUMO
Whether apoptotic index [AI] and/or Ki-67 labeling index [Ki-67LI] add prognostic information in bladder cancer remains unclear. Mean AI and Ki-67 LI increased with grade and stage in 147 superficial bladder tumors. AI (>1.7%) correlated with tumor size, grade and proliferation. Ki-67 LI (>10%) correlated with higher grade and stage. Tumor size and Ki-67 LI were independent predictors of disease-free and progression-free survival, respectively. Tumor size, patient's age and tumor's recurrence predicted overall survival. We conclude that conventional clinical parameters and Ki-67 LI define risk groups of bladder tumors, while AI has limited value.
Assuntos
Apoptose , Regulação Neoplásica da Expressão Gênica , Neoplasias da Bexiga Urinária/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Proliferação de Células , Estudos de Coortes , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Antígeno Ki-67/biossíntese , Masculino , Pessoa de Meia-IdadeRESUMO
The Gleason grading system remains one of the most powerful prognostic factors in prostate cancer and is the dominant method around the world in daily practice. It is based solely on the glandular architecture performed at low magnification. The Gleason grading system should be performed in needle core biopsies and radical prostatectomy specimens where it shows a reasonable degree of correlation between both specimens, and most importantly, it remains vital in the treatment decision-making process. This review summarizes the current status of Gleason grading in prostate cancer, incorporating recent proposals for the best contemporary practice of prostate cancer grading.
Assuntos
Próstata/patologia , Neoplasias da Próstata/diagnóstico , Humanos , Masculino , Guias de Prática Clínica como Assunto , Neoplasias da Próstata/classificação , Índice de Gravidade de DoençaRESUMO
OBJECTIVE: To report a clear cell renal cell carcinoma recipient of a metastasizing ductal carcinoma of the breast: A tumor-to-tumor metastasis. METHODS: A 71 year-old woman with a past history of breast carcinoma, diagnosed 12 years before, underwent a nephrectomy for an incidental kidney mass found in a routine imaging examination. RESULTS: Histological examination revealed foci of ductal carcinoma of the breast in an otherwise typical clear cell renal cell carcinoma of the kidney. Immunohistochemical examination confirmed a metastasis of an infiltrating breast carcinoma to a clear cell renal cell carcinoma (positive to GATA3, hormonal receptors and mamoglobin) in a clear cell renal cell carcinoma (positive to PAX8, CD10 and vimentin). CONCLUSIONS: Awareness of this phenomenon should always be kept in mind by urologist in patients with a known history of a previous malignancy and by pathologists when finding a renal tumor with an unusual or dimorphic morphology. Immunohistochemistry plays an important role to establish the exact diagnosis.
Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal/secundário , Carcinoma de Células Renais/patologia , Neoplasias Renais/secundário , Idoso , Feminino , HumanosRESUMO
High-grade papillary urothelial carcinoma with subepithelial connective tissue invasion (T1HG) is an aggressive disease at high risk of progression after transurethral resection/Bacillus Calmette-Guerin standardized therapy. The European Organization for Research and Treatment of Cancer has identified T1HG bladder carcinoma that is single and ≤3 cm in the largest dimension at first diagnosis as a category in which the prognosis cannot be further stratified based on conventional criteria. This category may benefit from biomarker analysis as a valuable tool to determine the patient's outcome. To further the issue of biomarkers in predicting aggressiveness in single T1HG bladder carcinoma ≤3 cm in greatest dimension at first diagnosis, we have conducted a validation study of the biomarker risk score set previously reported by our group. The study set included immunohistochemical detection of galectin-3, CD44, E-cadherin (E-CAD), CD138, p16, survivin, HYAL-1, and topoisomerase-IIα in 92 randomly selected specimens at participating institutions. Topoisomerase-IIα expression was identified as a predictor of disease-free survival. p16, survivin, and E-CAD expression predicted progression-free survival, but p16 and E-CAD also predicted overall survival. The current study validates a panel of immunohistochemical markers with the potential of being implemented in practice and supports the use of biomarkers in predicting aggressiveness in patients with first diagnosis of single T1HG bladder carcinoma ≤3 cm in greatest dimension and therefore in identifying patients who need closer surveillance or earlier aggressive treatment.
Assuntos
Antígenos de Neoplasias/análise , Biomarcadores Tumorais/análise , Caderinas/análise , Carcinoma Papilar/enzimologia , Inibidor p16 de Quinase Dependente de Ciclina/análise , DNA Topoisomerases Tipo II/análise , Proteínas de Ligação a DNA/análise , Proteínas Inibidoras de Apoptose/análise , Neoplasias da Bexiga Urinária/enzimologia , Idoso , Antígenos CD , Carcinoma Papilar/mortalidade , Carcinoma Papilar/patologia , Carcinoma Papilar/terapia , Intervalo Livre de Doença , Europa (Continente) , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Gradação de Tumores , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Reprodutibilidade dos Testes , Survivina , Fatores de Tempo , Resultado do Tratamento , Carga Tumoral , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/terapiaRESUMO
We examined the presence of human herpesvirus type 6 (HHV6) DNA in a series of 74 bladder carcinomas from a Mediterranean population to elucidate their possible role as cofactor in the development of bladder cancer with or without associated human papillomavirus (HPV) infection. HHV-6 type B DNA was present in 5 men (6.8%) out of the 74 tumors investigated; two of them had associated HPV-16 DNA in the same specimen. In one case that had associated urothelial carcinoma in situ, both HHV-6B and HPV-16 DNA were present. In conclusion, the low incidence of HHV-6B in bladder cancer and the ubiquitous nature of HHV-6 infection are more consistent with a bystander role rather than cofactor in the oncogenesis of bladder cancer.
Assuntos
Carcinoma/virologia , DNA Viral/análise , Herpesvirus Humano 6/genética , Herpesvirus Humano 6/patogenicidade , Infecções por Roseolovirus/complicações , Neoplasias da Bexiga Urinária/virologia , Adulto , Idoso , Feminino , Papillomavirus Humano 16/genética , Papillomavirus Humano 16/patogenicidade , Humanos , Masculino , Região do Mediterrâneo , Pessoa de Meia-Idade , Infecções por Papillomavirus/complicaçõesRESUMO
Atypical adenomatous hyperplasia (AAH) of the prostate is a microscopic proliferation of small acini that may be mistaken for adenocarcinoma. Although some data suggest that AAH is associated with adenocarcinoma arising in the transition zone, the clinical significance of this lesion is uncertain. Therefore we studied the DNA ploidy pattern and immunophenotype of AAH as compared with nodular hyperplasia and well-differentiated adenocarcinoma in 23 formalin-fixed, paraffin-embedded, whole-mounted retropubic prostatectomies. Representative sections were immunostained for keratin 34beta-E12, chromogranin, bcl-2, c-erbB-2, ki67-MIB1, and factor VIII (microvessel density). DNA ploidy was determined by image analysis and Feulgen-stained sections. There were rare scattered immunoreactive cells for chromogranin, bcl-2, and c-erbB-2 in nodular hyperplasia and AAH (mainly in the basal cell compartment) and in carcinoma. The ki67-MIB1 labeling index was different between nodular hyperplasia and AAH (p<0.001) and carcinoma (p=0.003) but not between AAH and carcinoma (p=0.203). Microvessel density was different between AAH and carcinoma (p=0.001) but not between nodular hyperplasia and AAH (p=0.105) or carcinoma (p=0.0820). All foci of nodular hyperplasia, AAH, and carcinoma were diploid. Ploidy status and our selected panel of antibodies did not discriminate among these 3 entities reliably.
Assuntos
DNA de Neoplasias , Ploidias , Doenças Prostáticas/patologia , Hiperplasia Prostática/patologia , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Idoso , Biomarcadores Tumorais/metabolismo , DNA de Neoplasias/genética , Humanos , Citometria por Imagem/métodos , Processamento de Imagem Assistida por Computador , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-Idade , Fenótipo , Doenças Prostáticas/genética , Doenças Prostáticas/metabolismo , Hiperplasia Prostática/genética , Hiperplasia Prostática/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologiaRESUMO
We studied 159 cases of superficial (stage Ta or T1) bladder tumors to determine the significance on survival of a subset of regulators of transition from G1 to S phase of the cell cycle (p53, p21Waf1, p27Kip1, cyclin D1, cyclin D3) and tumor proliferation (Ki-67 [MIB-1]). Clinical findings (patient age, sex, tumor size, grade, stage [Ta or T1]) were included in the analysis. Univariate analysis revealed association of tumor size (P = .0353), grade in stage Ta tumors (P = .0074), cyclin D1 expression (P = .0182), and Ki-67 index (P = .0033) with disease-free survival and of tumor size (P = .0005), stage (P = .0494), cyclin D3 expression (P = .0105), and Ki-67 index (P = .0272) with overall survival. Cox multivariate analysis revealed cyclin D1 expression and high proliferation index (disease-free) and tumor size, cyclin D3 expression, and high proliferation index (overall survival) as independent predictors. Results suggest that alterations of the progression from the G1 to S phase of the cell cycle are common in papillary urothelial bladder tumors. High tumor proliferation, expression of cyclins D1 and D3, and tumor size at diagnosis might be relevant predictors of survival in patients with stage Ta and T1 bladder urothelial tumors.
Assuntos
Carcinoma de Células de Transição/patologia , Ciclo Celular/fisiologia , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Ciclo Celular/biossíntese , Divisão Celular/fisiologia , Ciclina D1/biossíntese , Ciclina D3 , Inibidor de Quinase Dependente de Ciclina p21 , Inibidor de Quinase Dependente de Ciclina p27 , Ciclinas/biossíntese , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Fatores de Risco , Proteína Supressora de Tumor p53/biossíntese , Proteínas Supressoras de Tumor/biossínteseRESUMO
We present the clinicopathological features of 56 cases of the nested variant of urothelial bladder carcinoma. This is an uncommon variant of bladder cancer, recognized by the current WHO classification of urologic tumors. The nested component represented 100 % of the tumor in 24 cases. The architectural pattern of the tumor varied from solid expansile to infiltrative nests characterized by deceptively bland histologic features resembling von Brunn nests. Typical features of high-grade conventional urothelial carcinoma were present in 32 cases. Most neoplastic cells had nuclei of low to intermediate nuclear grade with occasional nuclear enlargement, most frequently seen in deep areas of tumor. The nested component expressed cytokeratins 7, 20, CAM5.2, and high molecular weight (34ßE12), p63, Ki67, p53, p27, and GATA3. Tumor extension was T1 (n = 9), minimally T2 (n = 10), T2a (n = 1), T2b (n = 4), T3a (n = 8), T3b (n = 13), and T4a (n = 11). On follow-up, 36 of patients died of or were alive with disease from 2 to 80 months (mean 21 months). Four patients died of other causes. Eleven other patients remained disease free. Univariate survival analysis showed no differences for nested carcinoma compared with conventional urothelial carcinoma. As in conventional urothelial carcinoma, in nested carcinoma of the bladder pT category defined different survival groups. In summary, nested variant of urothelial bladder carcinoma is typically associated with advanced stage. In samples of limited volume, it may be misdiagnosed as proliferation of von Brunn nests or other nested-like bladder lesions, delaying definitive therapy.
Assuntos
Carcinoma de Células de Transição/mortalidade , Carcinoma de Células de Transição/patologia , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologia , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células de Transição/metabolismo , Proliferação de Células , Feminino , Seguimentos , Fator de Transcrição GATA3/metabolismo , Humanos , Estimativa de Kaplan-Meier , Queratinas/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Taxa de Sobrevida , Proteína Supressora de Tumor p53/metabolismo , Neoplasias da Bexiga Urinária/metabolismoRESUMO
OBJECTIVE: To report two cases of late metastases of clear cell renal cell carcinoma. METHODS: Two patients, a male and a female with history of nephrectomy 17 and 16 years before for renal cell carcinomas, presented new tumours in the thyroid and pancreas, which were excised. RESULTS: Pathology reported that both lesions were clear cell tumours and immunohistochemically they were consistent with metastases from clear renal cell carcinomas. CONCLUSIONS: 1) Previous history of any type of carcinoma should suggest the possibility of metastases when facing a thyroid or pancreatic nodule. 2) All-life follow-up should be made, nephrectomy (resection) for a renal cell carcinoma. 3) In the presence of a clear cell tumour of the thyroid or pan-creatic glands, the differential diagnosis must always include metastatic renal cell carcinoma. 4) The treatment of choice is surgical resection.
Assuntos
Carcinoma de Células Renais/secundário , Neoplasias Renais/patologia , Neoplasias Pancreáticas/secundário , Neoplasias da Glândula Tireoide/secundário , Idoso , Carcinoma de Células Renais/patologia , Feminino , Humanos , Masculino , Neoplasias Pancreáticas/patologia , Neoplasias da Glândula Tireoide/patologia , Fatores de TempoRESUMO
INTRODUCTION: The aims of the present study were to investigate cyclooxygenase-2 expression in neoplastic cells from colorectal carcinoma and to study the role of cyclooxygenase-2 expression as a prognostic factor related to distant metastases and survival. PATIENTS AND METHOD: A retrospective study of 105 patients with sporadic colorectal cancer was performed. The patients underwent surgery at the General Surgery Department of the University Hospital of Jaén between 1991 and 1997. Several clinicopathological features were recorded: gender, tumor location, TNM stage, histological type and grade and the presence of venous or lymphatic invasion. The mean time of follow-up was 54 months. Immunohistochemistry: cyclooxygenase-2 expression was tested using avidin-biotin-peroxidase immunostaining. Both the intensity and extension of the stain were assessed. RESULTS: Cyclooxygenase-2 expression in neoplastic cells was considered to be positive in 38 cases (36.2%). No statistically significant relationship was found between cyclooxygenase-2 expression and the clinicopathological features recorded (P >.05). Tumor recurrence: Distant metastases were diagnosed in 14 patients (13.3%). Cyclooxygenase-2 did not show a significant relationship with metastases in the multivariate analysis (HR: 0.36; 95% confidence interval [CI]: 0.07-1.69). Survival: Mean survival time was 55 months. Multivariate analysis did not show cyclooxygenase-2 as an independent risk factor of death (HR: 0.51; 95% CI: 0.22-1.21). CONCLUSIONS: Cyclooxygenase-2 expression was not significantly related to clinical and histopathological features of the tumors nor was it an independent risk factor of tumour recurrence or survival.
Assuntos
Neoplasias Colorretais/metabolismo , Ciclo-Oxigenase 2/metabolismo , Adulto , Feminino , Humanos , Masculino , Estadiamento de Neoplasias , Prognóstico , Estudos RetrospectivosRESUMO
INTRODUCTION: Invasive growth pattern refers to the type of growth of the tumoral margins, whether infiltrating or noninfiltrating. The aim of the present study was to evaluate the invasive growth pattern (infiltrating/noninfiltrating) in colorectal cancer as a prognostic factor related to tumoral recurrence and survival. PATIENTS AND METHOD: We studied 105 patients with colorectal cancer who underwent radical surgery in the General Surgery Department of the Hospital Universitario Médico-Quirúrgico of Jaen between 1991 and 1997. The mean length of follow-up was 54 months. Regarding invasive growth pattern, 2 types of growth have been described: infiltrating and noninfiltrating. RESULTS: Tumoral invasion was infiltrating in 65 patients (62%). Tumoral recurrence: in 14 patients (13.3%) distant metastases were diagnosed. In the univariate analysis, infiltrative pattern was a statistically significant risk factor for distant metastases; however, this factor did not retain statistical significance in the multivariate analysis. Survival: 30 patients (28.5%) died from causes directly related to the neoplastic disease. The mean survival was 55 months. Infiltrating growth pattern was a statistically significant independent risk factor for death (HR = 2.50; 95% CI = 1.05-5.88). CONCLUSIONS: Infiltrating growth pattern was significantly related with the disease-free interval before metastases. Infiltrating growth was an independent prognostic factor of survival in colorectal cancer.
Assuntos
Neoplasias Colorretais/patologia , Neoplasias Colorretais/mortalidade , Progressão da Doença , Humanos , Invasividade Neoplásica , Estadiamento de Neoplasias , Prognóstico , Taxa de SobrevidaRESUMO
Sclerosing adenosis of the prostate is a pseudoneoplastic lesion that can mimic prostate cancer. Because the lesion is more common in the transition zone, which is only rarely sampled in needle biopsy, it is uncommon to see examples of this lesion in biopsy specimens. Because sampling of the transition zone of the prostate is likely to become more frequent, practicing surgical pathologists must be aware of the morphologic features of sclerosing adenosis of the prostate in needle biopsy specimens, in order to avoid misinterpretation of sclerosing adenosis of the prostate, a benign lesion, as prostate adenocarcinoma. We report the morphologic findings of sclerosing adenosis of the prostate in 3 needle biopsy specimens from 2 patients diagnosed as having sclerosing adenosis. We found a combination of histologic (mainly a cellular myxoid stroma and a double-cell population of acinar cells) and immunohistochemical features demonstrating a continuous basal cell layer with myoepithelial differentiation to be diagnostic.