Evaluation of prognostic utility of MIB-1 and p53 expression in pituitary adenomas: correlations with clinical behaviour and follow-up results

[Quantification of Ki-67 in PitNET (pituitary neuroendocrine tumors)/adenomas]

This study is the first to compare the determination of the Ki-67 index in pituitary neuroendocrine tumors (PitNET)/pituitary adenomas by pathologists with a computerized method (Cognition MasterSuite from VMScope, Berlin, Germany). PitNET/pituitary adenomas often show a low proliferation index. Observer variability is high, especially when estimating in this low percentage range. A more reliable determination would be possible using the four-eyes principle, but this cannot be realized continuously; thus, digital image analysis is a promising solution. In the study, there was clear agreement between the Ki-67 estimate by two experienced pathologists and the determination with the aid of digital image analysis. The digital image analysis system is excellent for determining the proliferation rate of PitNET/pituitary adenomas and can therefore be used to determine the "third" and "fourth eye".

Delineating the Spectrum of Pituitary Adenoma Based on the WHO 2017 Classification

BACKGROUND

The WHO 2017 classification of endocrine tumors incorporates lineage-specific transcription factors (TF) and hormone expression for the classification of pituitary adenoma (PA). There is paucity of reports describing the spectrum of PA based on this classification.

OBJECTIVE

The aim of this study was to delineate the spectrum of PA based on WHO 2017 classification of endocrine tumors.

MATERIALS AND METHODS

PA diagnosed in the year 2018 were studied. H and E and hormonal immunohistochemistry (IHC) for GH, PRL, ACTH, TSH, FSH, LH, CK, T-Pit and MIB-1 were performed and the results were analyzed.

RESULTS

The cohort included 88 cases. M: F ratio was 2:1. Clinically, 22 (25%) were functional and 66 (75%) were non-functional adenomas. Amongst the clinically functional adenomas, GH secreting adenomas were the commonest (68%). Majority (83%) of non-functional adenomas were hormone positive with gonadotroph adenomas being the commonest (72.7%). Eleven (12.5%) PA were clinically and hormonally silent. Three of these showed intense nuclear T-Pit positivity, classifying them under silent corticotroph adenoma. Lineage of the remaining eight adenomas remained undetermined, since, IHC for Pit-1 and SF-1 was not performed. The aggressive adenomas identified by IHC included sparsely granulated somatotroph adenoma, Crooke cell adenoma, silent corticotroph adenoma, densely granulated lactotroph adenoma in men and constituted 17% of the PA. Four (4/88) cases were clinically invasive.

CONCLUSION

A large majority of PA including aggressive adenomas can be identified by IHC. Addition of T-Pit helped to identify silent corticotroph adenoma. Pit -1 and SF-1 TF would help identify plurihormonal Pit-1 PA and null cell adenomas.

Predicting the Need for Desmopressin Treatment During Inpatient and After Discharge Following Endoscopic Sellar Surgery

Introduction

Postoperative diabetes insipidus (DI) is a common complication following endoscopic sellar surgery. However, the requirement of desmopressin treatment for patients with DI are heterogenous. Although the predictors of postoperative DI have been reported, whether these patients required desmopressin treatment remained uninvestigated. Predicting the need of desmopressin can benefit clinical decision making more directly than predicting the occurence of postoperative DI. This study aimed to identify variables that predict the need for desmopressin treatment following sellar surgery.

Methods

Patients undergoing endoscopic sellar surgery between 2016 and 2019 were retrospectively reviewed. Twenty-three variables, characterized as potential predictors for requiring desmopressin treatment, were analyzed. To assess the capability to generalize the identified predictors, external validation with receiver operating characteristic (ROC) analysis was performed using a second series from 2019 to 2020.

Results

Postoperative DI occurred in 40 of 159 included patients. Twelve patients required inpatient desmopressin treatment and 20 patients needed desmopressin prescription after discharge. The potential predictors of requiring any desmopressin use included higher peak sodium (Na) level (p = 0.007), lower minimum Na level (p = 0.043), and higher peak urine output (p = 0.006), but these were not supported by external validation. The predictors of requiring desmopressin after discharge included higher peak Na (p = 0.040) and minimum Na levels (p = 0.048), which were supported by external ROC validation showing areas under curve of 0.787, 0.611, and 0.898 for peak Na (p = 0.036), minimum Na (p = 0.460), and peak Na – minimum Na levels (p < 0.001), respectively. A criterion of peak Na ≥ 150 mmol/L or peak Na – minimum Na ≥ 10 predicted the need of desmopressin prescription after discharge. A postoperative management algorithm was proposed.

Conclusion

The required treatments for patients with postoperative DI following endoscopic sellar surgery are heterogenous. Elevated peak Na and large peak Na—minimum Na levels in the perioperative period predicted requiring desmopressin after hospital discharge. Patients with peak Na <150 mmol/L and peak Na—minimum Na <10 can be safely discharged without desmopressin prescription.

Evaluation of prognostic utility of Ki-67, P53, and O-6-methylguanine-DNA methyltransferase expression in pituitary tumors

BACKGROUND OR CONTEXT:

Pituitary adenoma (PA) is the most common pathology of the pituitary gland. Pituitary tumors were historically considered benign, however, from recent advances in pathological and molecular analyses, numerous prognostic markers have been identified, allowing a better characterization of tumor behavior and prediction of response to treatment and recurrences.

AIMS AND OBJECTIVES:

Evaluation of the epidemiological occurrence of pituitary tumors in our center and prediction of the benign, aggressive, or malignant nature of the tumor with the help of immunohistochemical markers (IHC) Ki-67, P53, and O-6-methylguanine-DNA methyltransferase (MGMT) along with radiology.

MATERIALS AND METHODS:

A prospective study was done in 33 cases. Patients with clinically suspected pituitary tumors and related symptoms and signs are referred from the endocrine outpatient department and subsequently operated at the neurosurgery department were selected. We have studied the clinical features, radiology, histopathology, and IHC with the help of Ki-67, P53, and MGMT of PA over 2 years.

RESULTS:

We have 94% (31/33) cases of PA among them 94% (29/31) cases are macroadenoma. The IHC was conducted on 30 cases (excluding 1 case of pituitary apoplexy) where Ki-67, p53, and MGMT have been used for IHC in order to analyze the prognosis of the PA, irrespective of the immunological subtype of the PA. In our study, only 13% (4 patients) had MGMT score 0 and 2 patients, among these 4 patients having above cutoff level of Ki-67 and p53 value, considered as aggressive (in case of Ki-67 >3% and >50% in case of p53). When comparing MGMT expression with recurrence, a high degree of significance was found (Mann–Whitney U-test, P = 0.0038). Most of the recurrent tumors (6/9) had MGMT score 1 or below and most of the nonrecurring tumor had MGMT score 2 or above. When comparing MGMT expression with aggressiveness, a high degree of significance was found (Mann–Whitney U-test, P < 0.0001). Finally, combining the radiological Ki-67, p53, and MGMT values, two cases of aggressive adenoma have been seen in our study, the remaining being benign adenomas (WHO classification 2004). We did not encounter any case of pituitary carcinoma. MGMT did not show any significant correlation with radiological grading and histology.

CONCLUSION:

The benign, aggressive, or malignant nature of PA can be effectively predicted with the help of IHC, such as Ki-67, p53, and MGMT. This helps in better patient management and predicts recurrences and prognosis.

The Prognostic Roles of the Ki-67 Proliferation Index, P53 Expression, Mitotic Index, and Radiological Tumor Invasion in Pituitary Adenomas

The fourth edition of the World Health Organization (WHO) classification of pituitary tumors recommended evaluation of tumor proliferation and invasion to identify aggressiveness. We aimed to assess the prognostic roles of the Ki-67 proliferation index, mitotic index, P53 expression, and cavernous sinus invasion in pituitary adenomas (PAs). Among the 601 patients who underwent transnasal/transsphenoidal adenomectomy from 2001 to 2016, 101 patients (16.8%) who had tumors with a high (≥ 3%) Ki-67 index (group A) and a control group consisting of 43 patients with a low (< 3%) Ki 67 index who were matched for age, gender, and tumor type were included. Mitotic index and P53 expressions were evaluated. Patient characteristics, histopathology reports, pre/postoperative magnetic resonance imaging (MRI), and follow-up data were assessed retrospectively. The frequency of macroadenomas and mean tumor size were greater in group A when compared to group B (67.4 vs. 94.1%, p< 0.01 and 25 ± 10.6 vs. 18 ± 11 mm, p< 0.01, respectively). Invasion to cavernous sinus was found in 53 (36.8%) patients and was more frequent in group A (p<0.01). The mean number of surgery was higher in group A than group B (p< 0.05). The mean follow-up period was 46.6 ± 34 months. The postoperative MRIs and follow-up data for at least 24 months were available in 117 patients. Recurrence risk was higher in group A than group B (p = 0.03). Tumors with high Ki-67 proliferation index were grouped as 3-5, 6-10, 11-15, and > 15%. The risk of recurrence was not different between groups of high Ki-67 index. The optimal cutoff point of the Ki-67 proliferation index that predicted recurrence was 2.5% with 84.6% sensitivity and 47.4% specificity. The cavernous sinus invasion on MRI was associated with recurrence (p = 0.03). Tumor size and recurrence risk were not associated with P53 expression. High P53 expression was related with cavernous sinus invasion (p = 0.03). The mitotic index was not associated with recurrence risk and tumor invasion. Recurrence risk was higher in tumors with ≥ 2 histopathological atypia criteria (p = 0.01). High Ki-67 index with a 2.5% cutoff point and cavernous sinus invasion on MRI are reliable markers for predicting recurrence in PAs. Recurrence risk is also higher in tumors with two histopathological aggressiveness criteria. Strict follow-up and more aggressive treatment approaches may be necessary for invasive-proliferative PAs.

Study of major genetic factors involved in pituitary tumorigenesis and their impact on clinical and biological characteristics of sporadic somatotropinomas and non-functioning pituitary adenomas

Genetic and functional aberrations of guanine nucleotide-binding protein, alpha stimulating (GNAS), aryl hydrocarbon receptor interacting protein (AIP), and pituitary tumor transforming gene (PTTG) are among the most prominent events in pituitary tumorigenesis. A cohort of Brazilian patients with somatotropinomas (n=41) and non-functioning pituitary adenomas (NFPA, n=21) from a single tertiary-referral center were evaluated for GNAS and AIP mutations and gene expression of AIP and PTTG. Results were compared to the clinical and biological (Ki67 and p53 expression) characteristics of tumors and their response to therapy, if applicable. Genetic analysis revealed that 27% of somatotropinomas and 4.8% of NFPA harbored GNAS mutations (P=0.05). However, no differences were observed in clinical characteristics, tumor extension, response to somatostatin analog therapy, hormonal/surgical remission rates, Ki67 index, and p53 expression between mutated and non-mutated somatotropinomas patients. PTTG overexpression (RQ mean=10.6, min=4.39, max=11.9) and AIP underexpression (RQ mean=0.56, min=0.46-max=0.92) were found in virtually all cases without a statistically significant relationship with clinical and biological tumor features. No patients exhibited somatic or germline pathogenic AIP mutations. In conclusion, mutations in GNAS and abnormal PTTG and AIP expression had no impact on tumor features and treatment outcomes in this cohort. Our data support some previous studies and point to the need for further investigations, probably involving epigenetic and transcriptome analysis, to improve our understanding of pituitary tumor behavior.

Association of Ki-67 Labelling Index and IL-17A with Pituitary Adenoma

The aim of the present study was to determine if the Ki-67 labelling index reflects invasiveness of pituitary adenoma and to evaluate IL-17A concentration in blood serum of pituitary adenoma patients. The study was conducted in the Hospital of Lithuanian University of Health Sciences. All pituitary adenomas were analysed based on magnetic resonance imaging findings. The suprasellar extension and sphenoid sinus invasion by pituitary adenoma were classified according to Hardy classification modified by Wilson. Knosp classification system was used to quantify the invasion of the cavernous sinus. The Ki-67 labelling index was obtained by immunohistochemical analysis with the monoclonal antibody, and serum levels of IL-17A were determined by enzyme-linked immunosorbent assay (ELISA). Sixty-nine PA tissue samples were investigated. Serum levels of IL–17A were determined in 60 patients with PA and 64 control subjects. Analysis revealed statistically significantly higher Ki-67 labelling index in invasive compared to noninvasive pituitary adenomas. Median serum IL-17A level was higher in the pituitary adenoma patients than in the control group. Conclusion. IL-17A might be a significant marker for patients with pituitary adenoma and Ki-67 labelling index in case of invasive pituitary adenomas.

Implications of the World Health Organization definition of atypia on surgically treated functional and non-functional pituitary adenomas

BACKGROUND

The World Health Organization (WHO) defines atypical pituitary adenomas as tumours with a MIB-1 labelling index ≥3%, p53 positivity and increased mitotic activity. Although a few reports have described the clinical and radiological correlates of atypia in pituitary adenomas, its impact on postoperative outcomes is not clearly defined.

METHOD

We reviewed preoperative and postoperative records of patients undergoing surgery for pituitary adenomas. Postoperative outcomes for functional adenomas (FPAs) were assessed according to contemporary definitions of remission and recurrence. For non-functional pituitary adenomas (NFPAs), extent of resection and disease progression were defined on the basis of postoperative magnetic resonance imaging.

RESULTS

Of 394 patients included for analysis, 29 cases (7.4%) fulfilled criteria for atypia. Patients with atypical tumours were significantly younger than those with typical adenomas. Remission was possible in 47.4% of FPAs, and was unrelated to the presence of atypia. In NFPAs, local invasiveness was negatively associated with extent of resection (OR, 0.255; 95% CI, 0.086-0.753; p < 0.001). In 93 NFPAs followed postoperatively with serial imaging over a mean duration of 37.5 months, disease progression/recurrence was significantly associated with the presence of atypia (OR, 5.058; 95% CI, 1.273-20.098; p = 0.021) on multivariate analysis.

CONCLUSIONS

Patients with atypical non-functional pituitary adenomas are at risk for postoperative recurrence and disease progression, suggesting a need for adjuvant therapy. However, only a small fraction of pituitary tumours demonstrate atypia, as defined by the WHO, limiting its clinical utility.

Decreased TAp63 and ΔNp63 mRNA Levels in Most Human Pituitary Adenomas Are Correlated with Notch3/Jagged1 Relative Expression

Despite recent advances in molecular genetics, the pituitary adenoma initiation, development, progress, and the molecular basis of their unique features are still poorly understood. In this sense, it is proposed that stem cell could be involved in pituitary adenoma tumorigenesis. It is suggested that TP63 has important functions in stem cells, and it may have interplay of TP63 and Notch and its ligand Jagged in this process. This study aimed to evaluate the distinct expression of TP63 isoforms (TAp63 and ΔNp63), as well as its correlation with Notch3 receptor and its ligand Jagged1 in human pituitary adenomas at the messenger RNA (mRNA) level. We included 77 pituitary adenoma tumor samples from patients who underwent surgical resection. The expression levels of TP63 isoforms (TAp63 and ΔNp63) and Notch3 and its ligand Jagged1 were evaluated by qRT-PCR using isoform-specific primers. We also evaluated proliferation index immunohistochemically using KI-67 antibody. The expression levels were associated with clinical outcomes, as age, gender, tumor size, and tumor subtype. In summary, we found that mRNA expression of both TP63 isoforms decreased in pituitary adenomas compared with normal pituitary control. On the other hand, there was an increase of relative Notch3 and Jagged1 mRNA expression in the majority of examined samples. The mRNA expression of three genes evaluated was correlated and statistically significantly. There was no significant association between gene expression and the analyzed clinical data. The current study has provided the first time evidence that Tap63 and ΔNp63 isoforms are underexpressed in most pituitary adenomas. These results are correlated with Notch3 and its ligand Jagged1 overexpression, corroborating previous studies pointing its antagonistic interactions.

The Predictive Value of Pathologic Features in Pituitary Adenoma and Correlation with Pituitary Adenoma Recurrence

Background

The 2004 World Health Organization classification introduced atypical pituitary adenoma (aPA), which was equivocally defined as invasion with increased mitotic activity that had a Ki-67 labeling index (LI) greater than 3%, and extensive p53 immunoreactivity. However, aPAs that exhibit all of these features are rare and the predictive value for recurrence in pituitary adenomas (PAs) remains uncertain. Thus, we sought to characterize pathological features of PAs that correlated with recurrence.

Methods

One hundred and sixty-seven cases of surgically resected PA or aPA were retrieved from 2011 to 2013 in Seoul St. Mary’s Hospital. Among them, 28 cases were confirmed to be recurrent, based on pathologic or radiologic examination. The pathologic characteristics including mitosis, invasion, Ki-67 LI and p53 immunoreactivity were analyzed in relation to recurrence.

Results

Analysis of the pathologic features indicated that only Ki-67 LI over 3% was significantly associated with tumor recurrence (p = .02). The cases with at least one pathologic feature showed significantly higher recurrence rates (p < .01). Analysis indicated that cases with two pathologic features, Ki-67 LI over 3% and extensive p53 immunoreactivity 20% or more, were significantly associated with tumor recurrence (p < .01).

Conclusions

Based on these results, PA tumor recurrence can be predicted by using mitosis, invasion, Ki-67 LI (3%), or extensive p53 immunoreactivity (≥ 20%). Assessment of these features is recommended for PA diagnosis for more accurate prediction of recurrence.

Epidemiological variations of aggressive growth hormone-secreting adenomas

Acromegaly is a chronic disorder characterized by increased morbidity and mortality in uncontrolled patients. Growth hormone-secreting pituitary adenoma is the hallmark in the majority of cases, generally considered as benign due to lack of distant metastases. However, clinical behavior in a certain proportion of these adenomas could be quite aggressive, causing difficulties in their management. Aggressive pituitary adenomas have some clinical, radiological, ultrastructural and molecular features in common and they are usually resistant to the standard treatment. In the recent years, efforts have been made to define the most appropriate markers of such adenomas that would allow an early detection and efficient individualized therapeutic strategy. The aim of this review is to give an update on epidemiology and certain markers predicting aggressive behavior of somatotropinomas.

Minichromosome maintenance protein 7 as prognostic marker of tumor aggressiveness in pituitary adenoma patients

BACKGROUND

Ki-67 labeling index (LI) is currently regarded as a useful prognostic marker of pituitary adenoma (PA) clinical behavior, although its relevance as a reliable clinical indicator is far from being universally accepted, since both validations and criticisms are found in the literature. Minichromosome maintenance 7 (MCM7), a cell-cycle regulator protein, has been recently proposed as a marker of tumor aggressiveness in tumors from many sites, including the CNS. Therefore, we evaluated MCM7, in comparison to Ki-67, as a potential marker of clinical outcome in PA.

DESIGN AND METHODS

In this single-institution retrospective study, 97 patients with PA (23 ACTH, 12 GH, 29 PRL, 10 FSH/LH, and 23 non-secreting adenomas) were recruited and the prognostic value of both MCM7 and Ki-67 was evaluated by immunohistochemical techniques. In addition, p53 nuclear expression and mitotic index were also evaluated.

RESULTS

Twenty-six of the 97 PA patients recurred during the follow-up period. Cox's regression analysis showed that high nuclear expression of MCM7 LI, unlike Ki-67 LI, was directly associated with a higher (7.7-fold) risk of recurrence/progression. Kaplan-Meier analysis of recurrence/progression-free survival curves revealed that patients with high MCM7 LI (≥15%) had a shorter recurrence/progression-free survival than those with low MCM7 LI (<15%). Moreover, among patients with invasive tumors, high MCM7 LI identified those with the highest risk of recurrence/progression.

CONCLUSIONS

Data from this study suggest that MCM7 is a prognostic marker of clinical outcome in PA patients, more reliable and informative than Ki-67.