Low DICER1 expression is associated with poor clinical outcome in adrenocortical carcinoma.

Low DICER1 expression was associated with poor outcome in several cancers. Recently, hot-spot DICER1 mutations were found in ovarian tumors, and TARBP2 truncating mutations in tumor cell lines with microsatellite instability. In this study, we assessed DICER1 e TRBP protein expression in 154 adult adrenocortical tumors (75 adenomas and 79 carcinomas). Expression of DICER1 and TARBP2 gene was assessed in a subgroup of 61 tumors. Additionally, we investigated mutations in metal biding sites located at the RNase IIIb domain of DICER1 and in the exon 5 of TARBP2 in 61 tumors. A strong DICER1 expression was demonstrated in 32% of adenomas and in 51% of carcinomas (p = 0.028). Similarly, DICER1 gene overexpression was more frequent in carcinomas (60%) than in adenomas (23%, p = 0.006). But, among adrenocortical carcinomas, a weak DICER1 expression was significantly more frequent in metastatic than in non-metastatic adrenocortical carcinomas (66% vs. 31%; p = 0.002). Additionally, a weak DICER1 expression was significantly correlated with a reduced overall (p = 0.004) and disease-free (p = 0.005) survival. In the multivariate analysis, a weak DICER1 expression (p = 0.048) remained as independent predictor of recurrence. Regarding TARBP2 gene, its protein and gene expression did not correlate with histopathological and clinical parameters. No variant was identified in hot spot areas of DICER1 and TARBP2. In conclusion, a weak DICER1 protein expression was associated with reduced disease-free and overall survival and was a predictor of recurrence in adrenocortical carcinomas.

Expression of LIN28 and its regulatory microRNAs in adult adrenocortical cancer.

OBJECTIVE: LIN28 control cells reprogramming and pluripotency mainly through miRNA regulation and has been overexpressed in many advanced cancers. In this study, we evaluated the prognostic role of LIN28 and its regulatory miRNAs in a large cohort of adrenocortical tumours (ACTs). PATIENTS AND METHODS: LIN28 protein expression was assessed in 266 adults ACTs (78 adenomas and 188 carcinomas) from Brazil and Germany. LIN28A and LIN28B gene expression was analysed in 59 ACTs (31 adenomas and 28 carcinomas) and copy number variation in 39 ACTs. In addition, we determined the expression of let-7 family, mir-9, mir-30 and mir-125 in 28 carcinomas. RESULTS: LIN28A gene was overexpressed in aggressive ACCs when compared with adenomas and nonaggressive ACCs, but no LIN28A copy number variation was found in ACTs. Unexpectedly, weak LIN28 protein expression was significantly associated with reduced disease-free survival in ACC patients (P = 0·01), but for overall survival only a trend was detectable (P = 0·117). In the multivariate analysis, only Ki67 index ≥10% (HR 4·6, P = 0·000) and weak LIN28 protein expression (HR 2·0, P = 0·03) were independent predictors of recurrence in ACC patients. Interestingly, mir-9 expression, a negative LIN28A/B regulator, was significantly higher in aggressive than in nonaggressive ACCs [2076 (from 36 to 9307) vs 133·4 (from 2·4 to 5193); P = 0·011] and was highly associated with reduced overall (P = 0·01) and disease-free survival (P = 0·01). However, mir-9 prognostic role should be further evaluated in a larger cohort. CONCLUSION: Weak LIN28 protein expression was associated with recurrence in ACCs. Additionally, overexpression of mir-9, a negative LIN28A regulator, was associated with poor outcome.

Analysis of the insulin-like growth factor 1 receptor gene in children born small for gestational age: in vitro characterization of a novel mutation (p.Arg511Trp).

BACKGROUND: Insulin-like growth factor 1 insensitivity caused by IGF1R mutations has been previously identified as one of the causes of growth impairment in children born small for gestational age (SGA). OBJECTIVE: To analyse the IGF1R in children born SGA. SUBJECTS: From an initial cohort of 54 sequential children born SGA, without catch-up growth, 25 children were selected for this IGF1R study due to the presence of serum IGF-1 values above the mean for their age and sex. METHODS: The proximal IGF1R promoter region, the entire coding region and the exon-intron boundaries were directly sequenced, and multiplex ligation-dependent probe amplification analysis was performed. Fibroblast cultures were developed from one patient with a mutation for the in vitro characterization of IGF-1 insensitivity. RESULTS: The copy number variation analysis did not identify deletions involving the IGF1R gene. We identified two children carrying heterozygous nucleotide substitutions in IGF1R: c.16G>A/p.Gly6Arg and c.1531C>T/p.Arg511Trp. The first variant (p.Gly6Arg) was identified in control subjects (0·3%) and in a relative with normal growth; thus, it was considered to be a rare benign allelic variation. The second variant (p.Arg511Trp) was not found in 306 alleles from control subjects, and it segregated with the growth impairment phenotype in the patient's family. Fibroblasts obtained from this patient had a significantly reduced proliferative response and AKT phosphorylation after IGF-1 stimulation compared with control fibroblasts. CONCLUSION: The identification of an inactivating IGF1R mutation in the present cohort should encourage further studies of larger series to establish the precise frequency of this molecular defect in children with growth impairment of a prenatal onset.

Steroidogenic factor 1 overexpression and gene amplification are more frequent in adrenocortical tumors from children than from adults.

BACKGROUND: Steroidogenic factor 1 (SF-1) is a key determinant of endocrine development and function of adrenal cortex. SF-1 overexpression and gene amplification were previously demonstrated in a small group of pediatric adrenocortical tumors. OBJECTIVE: Our objective was to determine the frequency of SF-1 protein expression and gene amplification in a large cohort of pediatric and adult adrenocortical tumors. PATIENTS: SF-1 protein expression was assessed in a cohort of 103 adrenocortical tumors from 36 children and 67 adults, whereas gene amplification was studied in 38 adrenocortical tumors (17 from children). METHODS: Tissue microarray, multiplex ligation-dependent probe amplification, and quantitative real-time PCR were used. RESULTS: A strong nuclear SF-1 expression was detected by tissue microarray in 56% (20 of 36) and 19% (13 of 67) of the pediatric and adult adrenocortical tumors, respectively (P = 0.0004). Increased SF-1 copy number was identified in 47% (eight of 17) and 10% (two of 21) of the pediatric and adult adrenocortical tumors, respectively (P = 0.02). All adrenocortical tumors with SF-1 gene amplification showed a strong SF-1 staining, whereas most of the tumors (61%) without SF-1 amplification displayed a weak or negative staining (P = 0.0008). Interestingly, a strong SF-1 staining was identified in five (29%) pediatric adrenocortical tumors without SF-1 amplification. The frequency of SF-1 overexpression and gene amplification was similar in adrenocortical adenomas and carcinomas. CONCLUSION: We demonstrated a higher frequency of SF-1 overexpression and gene amplification in pediatric than in adult adrenocortical tumors, suggesting an important role of SF-1 in pediatric adrenocortical tumorigenesis.