Proteomic Profiles Associated With Postsurgical Progression in Nonfunctioning Pituitary Adenomas.

CONTEXT: There is a lack of reliable biomarkers capable of predicting postoperative tumor progression of nonfunctioning pituitary adenomas (NFPAs). OBJECTIVE: To discover proteomic profiles associated with postoperative tumor progression in patients with NFPAs. This was a case-controlled exploratory study at a tertiary university hospital. Tissue samples were obtained from 46 patients with residual tumor following surgery for NFPAs of gonadotroph lineage. Two patient groups were compared: patients requiring reintervention due to residual tumor progression (cases; reintervention group, n = 29) and patients with a residual tumor showing no progression for a minimum of 5 years (controls; radiologically stable group, n = 17). Differentially expressed proteins (DEPs) between patient groups were measured. RESULTS: Global quantitative proteomic analysis identified 4074 proteins, of which 550 were differentially expressed between the 2 groups (fold change >80%, false discovery rate-adjusted P ≤ .05). Principal component analysis showed good separation between the 2 groups. Functional enrichment analysis of the DEPs indicated processes involving translation, ROBO-receptor signaling, energy metabolism, mRNA metabolism, and RNA splicing. Several upregulated proteins in the reintervention group, including SNRPD1, SRSF10, SWAP-70, and PSMB1, are associated with tumor progression in other cancer types. CONCLUSION: This is the first exploratory study analyzing proteomic profiles as markers of postoperative tumor progression in NFPAs. The findings clearly showed different profiles between tumors with indolent postoperative behavior and those with postoperative tumor progression. Both enriched pathways involving DEPs and specific upregulated proteins have previously been associated with tumor aggressiveness. These results suggest the value of proteomic profiling for predicting tumor progression in patients with NFPAs.

Genome-wide DNA Methylation Differences in Nonfunctioning Pituitary Adenomas With and Without Postsurgical Progression.

CONTEXT: Tumor progression in surgically treated patients with nonfunctioning pituitary adenomas (NFPAs) is associated with excess mortality. Reliable biomarkers allowing early identification of tumor progression are missing. OBJECTIVE: To explore DNA methylation patterns associated with tumor progression in NFPA patients. METHODS: This case-controlled exploratory trial at a university hospital studied patients who underwent surgery for NFPA that had immunohistochemical characteristics of a gonadotropinoma. Cases included patients requiring reintervention due to tumor progression (reintervention group, n = 26) and controls who had a postoperative residual tumor without tumor progression for at least 5 years (radiologically stable group, n = 17). Genome-wide methylation data from each tumor sample were analyzed using the Infinium MethylationEPIC BeadChip platform. RESULTS: The analysis showed that 605 CpG positions were significantly differently methylated (differently methylated positions, DMPs) between the patient groups (false discovery rate adjusted P value < 0.05, beta value > 0.2), mapping to 389 genes. The largest number of DMPs were detected in the genes NUP93 and LGALS1. The 3 hypomethylated DMPs and the 3 hypermethylated DMPs with the lowest P values were all significantly (P < 0.05) and individually associated with reintervention-free survival. One of the hypermethylated DMPs with the lowest P value was located in the gene GABRA1. CONCLUSION: In this exploratory study, DNA methylation patterns in NFPA patients were associated with postoperative tumor progression requiring reintervention. The DMPs included genes that have been previously associated with tumor development. Our study is a step toward finding epigenetic signatures to predict tumor progression in patients with NFPA.

MCM7 as a marker of postsurgical progression in non-functioning pituitary adenomas.

OBJECTIVE: Current markers predicting tumour progression of pituitary adenomas after surgery are insufficient. Our objective was to investigate if minichromosome maintenance protein 7 (MCM7) expression predicts tumour progression in non-functioning pituitary adenomas (NFPAs). METHODS: In a cohort study of surgically treated NFPAs, two groups with distinctly different behaviour of a residual tumour were selected: one group requiring reintervention due to tumour progression (reintervention group, n = 57) and one with residual tumours without progression (radiologically stable group, n = 40). MCM7, Ki-67, oestrogen receptor-α expression, mitotic index and tumour subtype were assessed by immunohistochemistry, and their association with tumour progression requiring reintervention was analysed. RESULTS: Median (IQR) MCM7 expression was 7.4% (2.4-15.2) in the reintervention group compared with 2.0% (0.6-5.3) in the radiologically stable group (P <0.0001). Cox regression analysis showed an association between high (>13%) MCM7 expression and reintervention (HR: 3.1; 95% CI:1.7-5.4; P = 0.00012). The probability for reintervention within 6 years for patients with high MCM7 was 93%. Ki-67 expression >3% (P = 0.00062), age ≤55 years (P = 0.00034) and mitotic index≥1 (P = 0.024) were also associated with reintervention. Using a receiver operating characteristics curve, a predictive model for reintervention with all the above predictors yielded an area under the curve of 82%. All eight patients with both high MCM7 and high Ki-67 needed reintervention. CONCLUSION: This cohort study shows that expression of MCM7 is a predictor for clinically significant postoperative tumour progression. Together with age, Ki-67 and mitotic index, MCM7 might be of added value as a predictive marker when managing patients with NFPA after surgery.