Phospho-histone H3 (pHH3) immuno-reactivity as a prognostic marker in non-functioning pituitary adenomas

SOX2 expression in prostate cancer drives resistance to nuclear hormone receptor signaling inhibition through the WEE1/CDK1 signaling axis

The development of androgen receptor signaling inhibitor (ARSI) drug resistance in prostate cancer (PC) remains therapeutically challenging. Our group has described the role of sex determining region Y-box 2 (SOX2) overexpression in ARSI-resistant PC. Continuing this work, we report that NR3C1, the gene encoding glucocorticoid receptor (GR), is a novel SOX2 target in PC, positively regulating its expression. Similar to ARSI treatment, SOX2-positive PC cells are insensitive to GR signaling inhibition using a GR modulating therapy. To understand SOX2-mediated nuclear hormone receptor signaling inhibitor (NHRSI) insensitivity, we performed RNA-seq in SOX2-positive and -negative PC cells following NHRSI treatment. RNA-seq prioritized differentially regulated genes mediating the cell cycle, including G2 checkpoint WEE1 Kinase (WEE1) and cyclin-dependent kinase 1 (CDK1). Additionally, WEE1 and CDK1 were differentially expressed in PC patient tumors dichotomized by high vs low SOX2 gene expression. Importantly, pharmacological targeting of WEE1 (WEE1i) in combination with an ARSI or GR modulator re-sensitizes SOX2-positive PC cells to nuclear hormone receptor signaling inhibition in vitro, and WEE1i combined with ARSI significantly slowed tumor growth in vivo. Collectively, our data suggest SOX2 predicts NHRSI resistance, and simultaneously indicates the addition of WEE1i to improve therapeutic efficacy of NHRSIs in SOX2-positive PC.

Aggressive nonfunctioning pituitary neuroendocrine tumors

Nonfunctioning pituitary neuroendocrine tumors (NF-PitNETs) are tumors that are not associated with clinical evidence of hormonal hypersecretion. According to the World Health Organization (WHO), there are some subtypes of PitNETs that exhibit more aggressive behavior than others. Among the types of potentially aggressive PitNETs, three are nonfunctional: silent sparsely granulated somatotropinomas, silent corticotropinomas, and poorly differentiated PIT-1 lineage tumors. Several biological markers have been investigated in NF-PitNETs. However, there is no single biomarker able to independently predict aggressive behavior in NF-PitNETs. Thus, a more complex and multidisciplinary proposal of a comprehensive definition of aggressive NF-PitNETs is necessary. Here, we suggest a combined and more complete criterion for the NF-PitNETs classification. We propose that aggressiveness is due to a multifactorial combination, and we emphasize the need to include new emerging markers that are involved in the aggressiveness of NF-PitNETs and the need to identify.

TERT promoter methylation is significantly associated with TERT upregulation and disease progression in pituitary adenomas

PURPOSE

Alterations in the promoter of the telomerase reverse transcriptase (TERT) gene are a major mechanism of upregulating telomerase, which plays a crucial role in tumor development. Mutations in the TERT promoter have been observed in a subset of brain tumors, including adult gliomas and high-grade meningiomas. In pituitary adenomas (PAs), however, abnormalities in TERT are not fully understood. The present study aimed to investigate not only mutational but also methylation changes in the TERT promoter in PAs and to analyze their correlations with clinical variables.

METHODS

We retrospectively studied 70 PAs consisting of 53 primary and 17 recurrent samples. Clinical data, including age at surgery, sex, largest tumor dimension, tumor subtype, resection rate, and progression-free survival (PFS), were obtained from medical records. We investigated TERT promoter hotspot mutations via Sanger sequencing and quantified the methylation status of the TERT promoter using methylation-sensitive high-resolution melting analysis (MS-HRM). Additionally, we investigated TERT mRNA expression using real-time quantitative PCR.

RESULTS

TERT promoter hotspot mutations were not observed in any PA sample, while 16% of PAs exhibited TERT promoter methylation. PAs with methylated TERT promoters were significantly more likely to show disease progression, shorter PFS, and higher TERT expression levels compared to those with unmethylated promoters.

CONCLUSIONS

This is the first study showing that TERT promoter methylation is associated with disease progression and shorter PFS as well as upregulated TERT expression in PAs. Our results suggest that TERT promoter methylation may be a potential biomarker for predicting tumor recurrence in PAs.

Nonfunctioning giant pituitary adenomas: Invasiveness and recurrence

BACKGROUND

We report our surgical series of 35 patients with giant nonfunctioning pituitary adenomas (GNFPA). We analyzed the rule of Ki-67 antigen expression in predicting recurrence.

METHODS

Thirty-five patients were operated between 2000 and 2010. Suprassellar extension of the tumors were classified according to Hardy and Mohr based on magnetic resonance (MR) studies. Pituitary endocrine function and MR scans were assessed preoperatively and at 1, 6, and 12 months postoperatively. Immunohistochemical studies were based in regard to the expression of the proliferative Ki-67 index and the hormonal receptor for luteinizing hormone, follicle stimulating hormone, growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, and prolactin. Tumors specimens were obtained from 35 patients with GNFPA. Endoscopic transsphenoidal surgery was the approach of choice.

RESULTS

Thirty-five patients were submitted to 49 surgeries, 44 (89.8%) were transsphenoidal and 5 (10.2%) were transcranial. The most frequent preoperative complaints were visual acuity impairment and visual field defect in 25 (71.2%) and 23 (65.7%) cases, respectively. Improvement of visual acuitiy and visual field deficit after surgery was seen in 20 (80%) and 17 (73.9%) patients, respectively. Endocrinological deficits were encountered in 20 patients (57.1%). After surgery, 18 patients (51.4%) required hormonal replacement. Three patients had visual symptoms related to pituitary apoplexy and recovered after surgery. The Ki-67 labeling index (LI) ranged from <1% to 4.8%. The rate of recurrence in tumors with Ki-67 <3% was 7.7% (2 patients), Ki-67 >3% was present in 5 patients and the recurrence committed 3 patients.

CONCLUSION

In our series, regardless the improvement of visual function and compressing symptoms, 5 patients with expression of Ki-67 LI more than 3% experienced a recurrence.

Current breast cancer proliferative markers correlate variably based on decoupled duration of cell cycle phases

Mitotic count, PhH3, and MIB-1 are used as measures of the proportion of proliferating malignant cells in surgical pathology. They highlight different stages of the cell cycle, but little is known about how this affects their counts. This study assesses the strength of their correlations and attempts to determine the relationship between them. Proliferation counts for forty-nine consecutive cases of invasive breast carcinomas were analyzed, with the same tumor area on each stain counted using digital image analysis. The integrated optical density (IOD) of nuclei was measured as an approximation of nuclear DNA content. PhH3 strongly correlated with mitotic count (r = 0.94). Weaker correlations were found between MIB-1 versus PhH3 (r = 0.79) and mitotic count (r = 0.83). Nuclear IOD showed stronger correlation with MIB-1 (r = 0.37) than to mitotic count (r = 0.23) and PhH3 (r = 0.34). With evidence from a literature review, it is suggested that the weaker correlations with MIB-1 are not explained by count imprecision or error, but relies on temporal decorrelation between cell cycle phases. Consequences on correlation between these proliferative markers are illustrated by mathematical models.

Prognostic significance of phospho-histone H3 in prostate carcinoma

PURPOSE

Prostate cancer is the second most common cancer in men and the sixth most common cause of death from cancer in men worldwide. Currently, a sufficient pathological distinction between patients requiring further treatment and those for which active surveillance remains an option is still lacking, which leads to the problem of overtreatment. Cell proliferation is routinely assessed by detecting Ki-67 antigen. While Ki-67 is expressed throughout the interphase of proliferating cells, phosphorylation of the chromatin constituent histone H3 occurs only during the late G2 phase and mitosis thus providing a more strict assessment of the mitotic activity. We undertook this study to test whether expression of the recently introduced proliferation marker phospho-histone H3 (pHH3) in prostate carcinoma tissue sections exhibits prognostic significance in comparison with Ki-67.

METHODS

Protein expression of pHH3 and Ki-67 was assessed on TMA consisting of paraffin-embedded tissue from men that had undergone radical prostatectomy. The analysis included triplicate tissue cores of a total of 339 tumor foci. Immunohistochemical staining of pHH3 and Ki-67 was performed and analyzed using Definiens imaging software.

RESULTS

Prostate cancer tissue exhibited a significantly higher frequency of pHH3-positive cells compared to benign prostate tissue. pHH3 expression was significantly correlated with Ki-67 expression. Furthermore, statistical analysis revealed positive correlation between pHH3 expression and PSA levels at diagnosis and in addition negatively correlated with overall survival. In contrast to Ki-67 staining, pHH3 expression did not correlate with Gleason grade.

CONCLUSION

Our data point to a conceivable role of pHH3 as prognostic biomarker in prostate carcinoma.