MiR-137's Tumor Suppression on Prolactinomas by Targeting MITF and Modulating Wnt Signaling Pathway

MicroRNA Is Downregulated in Invasive Non-Functioning Pituitary Adenomas

The study aimed to analyze hsa-miR-16-5p, hsa-miR-143-3p, hsa-miR-423-5p, hsa-miR-137-3p, hsa-miR-489-5p, hsa-miR-520-3p, hsa-miR-486-5p, and hsa-miR-200a-3p expression in the serum of patients with invasive non-functioning pituitary adenomas (NFPAs) and prolactinomas, as candidates for non-invasive biomarkers. The study included 62 patients with NFPAs and 18 with macroprolactinoma who qualified for transsphenoidal surgical resection. MicroRNAs were isolated from serum samples. The expression levels of hsa-miR-16-5p, hsa-miR-143-3p, hsa-miR-423-5p, hsa-miR-137-3p, hsa-miR-489-5p, hsa-miR-520-3p, hsa-miR-486-5p, and hsa-miR-200a-3p were determined using TaqMan MicroRNA assays. The statistical analyses were performed with MedCalc. The total concentration of microRNA was significantly lower in NFPAs than in the CG (p = 0.0419). ROC curve analysis showed that the cutoff point of miRNA lower than 10.73 predicted the PA (sensitivity = 70.0%; specificity = 57.7%; AUC = 0.629; p = 0.052). No correlation between selected miRNAs and tumor type was found: hsa-miR-143-3p (p = 0.4610), hsa-miR-16-5p (p = 0.8767), and hsa-miR-423-5p (p = 0.1459). miRNA expression also did not correlate with invasiveness (cavernous or sphenoid sinus invasion, optic chiasm compression). Although the total expression of microRNA was significantly lower in NFPAs, hsa-miR-16-5p, hsa-miR-143-3p, and hsa-miR-423-5p are not useful as non-invasive biomarkers in patients with invasive non-functioning pituitary adenomas and prolactinomas.

Liquid Biopsy in Pituitary Neuroendocrine Tumors-Potential Biomarkers for Diagnosis, Prognosis, and Therapy

Pituitary neuroendocrine tumors (PitNETs) are slow-growing neoplasms with various clinical presentations, often leading to diagnostic challenges. While neuroimaging assessment and histopathological evaluation remain the gold standard for diagnosis, emerging research highlights the potential of liquid biopsy, mainly through the analysis of circulating non-coding RNAs (ncRNAs), as a promising diagnostic and prognostic tool. Recent studies have demonstrated distinct expression profiles in different types and subtypes of tumors, with implications in assessing tumor aggressiveness and predicting treatment response. The current article summarizes data about potential biofluid markers implicated in PitNET development, mainly circulating tumor DNA (ctDNA), cell-free RNAs (cfRNA), circulating tumor cells (CTCs), and exosomes. Many studies on genetic and molecular markers in PitNET tissue samples provide exciting information about tumor biology, but to date, specific studies on liquid biopsy biomarkers are still few. Over the past years, a certain understanding of the mechanisms involved in pituitary tumorigenesis has been gained, including the landscape of genomic alterations, changes in epigenetic profile, crucial molecules involved in specific signaling pathways, and non-coding RNA molecules with critical roles in malignant transformation. Genetic and molecular characterization of the PitNETs could help distinguish between functional and non-functional PitNETs, different types and subtypes of pituitary tumors, and invasive and non-invasive forms. Further studies are required to identify and validate innovative biomarkers or therapeutic targets for treating PitNET. Integrating liquid biopsy into clinical workflows could revolutionize the management of pituitary adenomas, enabling more personalized and less invasive diagnostic and therapeutic strategies.

MicroRNA networks in prolactinoma tumorigenesis: a scoping review

BACKGROUND

Prolactinoma is the leading type of pituitary adenoma. Aside from the mass-like effect of prolactinoma, its hormonal effect is the main pathological cause of endocrine dysregulation and infertility. The dopamine agonist administration and surgical resection are the current mainstream anti-neoplastic treatments for affected patients; however, tumor fibrosis, tumor invasion, dopamine agonist resistance, and gain prolactinomas are clinical challenges for treating affected patients. Therefore, there is a need to develop novel treatments for these patients. Although growing evidence has highlighted the significance of dysregulated microRNA (miRNA) expression in various malignancies, no study has systematically investigated the significance of miRNA networks and their therapeutic potential in prolactinoma. For this aim, the current scoping review was performed according to the systematic reviews and meta-analyses extension for scoping reviews (PRISMA-ScR) guideline.

MAIN BODY

The systematic study on PubMed, Web of Science, Scopus, and Embase databases has shown that miR-200c, miR-217, miR-93a, miR-93, miR-1299, and miR-9 are the oncogenic miRNAs and miR-137, miR-145-5p, miR-197-3p, miR-29a-3p, miR-489, miR-199a-5p, miR-124, miR-212, miR-129-5p, miR-130a-3p, miR-326, miR-432, miR-548c-3p, miR-570, miR-15, miR-16, miR-26a, miR-196a2, and let-7a are tumor-suppressive miRNAs in prolactinoma tumorigenesis.

CONCLUSION

In summary, inhibiting the oncogenic miRNAs and ectopic expression of tumor-suppressive miRNAs can decrease prolactin secretion, reduce tumor invasion and migration, enhance dopamine agonist efficacy, and inhibit prolactinoma development. These findings can serve as a blueprint for future translational studies investigating miR-based therapeutics for prolactinoma.

The emerging role of miRNAs in pituitary adenomas: From molecular signatures to diagnostic potential

Pituitary adenomas (PAs) are an array of tumors originating from the pituitary gland. PAs are sorted as functional or nonfunctional according to their hormonal activity and classified according to size into microadenomas and macroadenomas. Still, the cellular events that trigger the transformations in pituitary neoplasms are not fully understood, and the current classification methods do not precisely predict clinical behavior. A rising number of researches have emphasized the role of miRNAs, that drawn more attention as oncogenic molecules or tumor suppressors. The etiopathological mechanisms of PAs include multiple molecular cascades that are influenced by different miRNAs. miRNAs control the cell cycle control, pro- or antiapoptotic processes, and tumor invasion and metastasis. miRNAs offer a novel perspective on tumor features and behaviors and might be valuable in prognostication and therapeutic plans. In pituitary adenomas, miRNAs showed a specific expression pattern depending on their size, cell origin, remission, and treatments. Screening miRNA expression patterns is promising to monitor and evaluate recurrence, as well as to investigate the efficacy of radiation and chemotherapy for PAs exhibiting aggressive behavior. Thus, the current review investigated the interplay of the miRNAs' pivotal role in offering new opportunities to translate these innovative epigenetic tools into healthcare applications.

Aggressive PitNETs and Potential Target Therapies: A Systematic Review of Molecular and Genetic Pathways

Recently, advances in molecular biology and bioinformatics have allowed a more thorough understanding of tumorigenesis in aggressive PitNETs (pituitary neuroendocrine tumors) through the identification of specific essential genes, crucial molecular pathways, regulators, and effects of the tumoral microenvironment. Target therapies have been developed to cure oncology patients refractory to traditional treatments, introducing the concept of precision medicine. Preliminary data on PitNETs are derived from preclinical studies conducted on cell cultures, animal models, and a few case reports or small case series. This study comprehensively reviews the principal pathways involved in aggressive PitNETs, describing the potential target therapies. A search was conducted on Pubmed, Scopus, and Web of Science for English papers published between 1 January 2004, and 15 June 2023. 254 were selected, and the topics related to aggressive PitNETs were recorded and discussed in detail: epigenetic aspects, membrane proteins and receptors, metalloprotease, molecular pathways, PPRK, and the immune microenvironment. A comprehensive comprehension of the molecular mechanisms linked to PitNETs' aggressiveness and invasiveness is crucial. Despite promising preliminary findings, additional research and clinical trials are necessary to confirm the indications and effectiveness of target therapies for PitNETs.

Research progress on the role of the Wnt signaling pathway in pituitary adenoma

Pituitary adenoma (PA) is the third most common central nervous system tumor originating from the anterior pituitary, but its pathogenesis remains unclear. The Wnt signaling pathway is a conserved pathway involved in cell proliferation, Self-renewal of stem cells, and cell differentiation. It is related to the occurrence of various tumors, including PA. This article reviews the latest developments in Wnt pathway inhibitors and pathway-targeted drugs. It discusses the possibility of combining Wnt pathway inhibitors with immunotherapy to provide a theoretical basis for the combined treatment of PA.

Therapeutic response to pazopanib: case report and literature review on molecular abnormalities of aggressive prolactinomas

Introduction

Aggressive prolactinomas (APRLs) pose a significant clinical challenge due to their high rate of regrowth and potentially life-threatening complications. In this study, we present a case of a patient with an APRL who had a trial of multiple therapeutic modalities with the aim to provide a review of molecular abnormalities and management of APRLs by corroborating our experience with previous literature.

Methods

A total of 268 articles were reviewed and 46 were included. Case reports and series, and studies that investigated the molecular and/or genetic analysis of APRLs were included. Special care was taken to include studies describing prolactinomas that would fall under the APRL subtype according to the European Society of Endocrinology guidelines; however, the author did not label the tumor as "aggressive" or "atypical". Addiontionally, we present a case report of a 56-year-old man presented with an invasive APRL that was resistant to multiple treatment modalities.

Results

Literature review revealed multiple molecular abnormalities of APRLs including mutations in and/or deregulation of ADAMTS6, MMP-9, PITX1, VEGF, POU6F2, CDKN2A, and Rb genes. Mismatch repair genes, downregulation of microRNAs, and hypermethylation of specific genes including RASSF1A, p27, and MGMT were found to be directly associated with the aggressiveness of prolactinomas. APRL receptor analysis showed that low levels of estrogen receptor (ER) and an increase in somatostatin receptors (SSTR5) and epidermal growth factor receptors (EGFR) were associated with increased invasiveness and higher proliferation activity. Our patient had positive immunohistochemistry staining for PD-L1, MSH2, and MSH6, while microarray analysis revealed mutations in the CDKN2A and POU6F2 genes. Despite undergoing two surgical resections, radiotherapy, and taking dopamine agonists, the tumor continued to progress. The patient was administered pazopanib, which resulted in a positive response and the patient remained progression-free for six months. However, subsequent observations revealed tumor progression. The patient was started on PD-L1 inhibitor pembrolizumab, yet the tumor continued to progress.

Conclusion

APRLs are complex tumors that require a multidisciplinary management approach. Knowledge of the molecular underpinnings of these tumors is critical for understanding their pathogenesis and identifying potential targets for precision medical therapy.

Functional Screen for microRNAs Suppressing Anchorage-Independent Growth in Human Cervical Cancer Cells

The progression of anchorage-dependent epithelial cells to anchorage-independent growth represents a critical hallmark of malignant transformation. Using an in vitro model of human papillomavirus (HPV)-induced transformation, we previously showed that acquisition of anchorage-independent growth is associated with marked (epi)genetic changes, including altered expression of microRNAs. However, the laborious nature of the conventional growth method in soft agar to measure this phenotype hampers a high-throughput analysis. We developed alternative functional screening methods using 96- and 384-well ultra-low attachment plates to systematically investigate microRNAs regulating anchorage-independent growth. SiHa cervical cancer cells were transfected with a microRNA mimic library (n = 2019) and evaluated for cell viability. We identified 84 microRNAs that consistently suppressed growth in three independent experiments. Further validation in three cell lines and comparison of growth in adherent and ultra-low attachment plates yielded 40 microRNAs that specifically reduced anchorage-independent growth. In conclusion, ultra-low attachment plates are a promising alternative for soft-agar assays to study anchorage-independent growth and are suitable for high-throughput functional screening. Anchorage independence suppressing microRNAs identified through our screen were successfully validated in three cell lines. These microRNAs may provide specific biomarkers for detecting and treating HPV-induced precancerous lesions progressing to invasive cancer, the most critical stage during cervical cancer development.

The SF3B1R625H mutation promotes prolactinoma tumor progression through aberrant splicing of DLG1

Background

Recently, a hotspot mutation in prolactinoma was observed in splicing factor 3b subunit 1 (SF3B1^R625H), but its functional effects and underlying molecular mechanisms remain largely unexplored.

Methods

Using the CRISPR/Cas9 genome editing system and rat pituitary GH3 cells, we generated heterozygous Sf3b1^R625H mutant cells. Sanger and whole-genome sequencing were conducted to verify the introduction of this mutation. Transcriptome analysis was performed in SF3B1-wild-type versus mutant human prolactinoma samples and GH3 cells. RT-PCR and minigene reporter assays were conducted to verify aberrant splicing. The functional consequences of SF3B1^R625H were evaluated in vitro and in vivo. Critical makers of epithelial-mesenchymal transition and key components were detected using western blot, immunohistochemistry, and immunofluorescence. Suppressing proteins was achieved using siRNA.

Results

Transcriptomic analysis of prolactinomas and heterozygous mutant cells revealed that the SF3B1^R625H allele led to different alterations in splicing properties, affecting different genes in different species. SF3B1^R625H promoted aberrant splicing and DLG1 suppression in both rat cells and human tumors. In addition, SF3B1^R625H and knocking down DLG1 promoted cell migration, invasion, and epithelial-mesenchymal transition through PI3K/Akt pathway.

Conclusions

Our findings elucidate a mechanism through which mutant SF3B1 promotes tumor progression and may provide a potent molecular therapeutic target for prolactinomas with the SF3B1^R625H mutation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02245-0.

MicroRNAs in Dopamine Agonist-Resistant Prolactinoma

Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of cabergoline-treated individuals exhibit resistance to DAs. In addition, the mechanism underlying this phenomenon remains elusive. In this study, we summarize the major findings regarding the role of microRNAs (miRNAs) in the pathogenesis of DA-resistant prolactinoma (DARP). Currently available evidence suggests that miRNAs are usually dysregulated in DARP and that, although controversial, the dysregulated miRNAs target the transforming growth factor (TGF)-β, dopamine 2 receptor (D2R), or estradiol (E2)/estrogen receptor (ER) signaling pathways to mediate the therapeutic effect of DAs. These findings provide new incentives for research on innovative strategies for predicting patients' responsiveness to dopamine therapies and for developing treatment approaches. Unfortunately, recent studies tended to focus exclusively on the differential miRNA expression profiles between DARP and dopamine-sensitive prolactinoma, and no definitive consensus has been reached regarding the role of these miRNAs in the modulation mechanism. Therefore, current and future efforts should be directed toward the exploration of the mechanism underlying the dysregulation of miRNAs as well as of the target proteins that are affected by the dysregulated miRNAs. Furthermore, the modulation of the expression of dysregulated miRNAs, which target the D2R, TGF-β, or E2/ER signaling pathways, might be a promising alternative to treat patients with DARP and improve their prognosis.

The Emerging Role of Non-Coding RNAs in Pituitary Gland Tumors and Meningioma

Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) are non-coding transcripts which are involved in the pathogenesis of pituitary gland tumors. LncRNAs that participate in the pathogenesis of pituitary gland tumors mainly serve as sponges for miRNAs. CLRN1-AS1/miR-217, XIST/miR-424-5p, H19/miR-93a, LINC00473/miR-502-3p, SNHG7/miR-449a, MEG8/miR-454-3p, MEG3/miR-23b-3p, MEG3/miR-376B-3P, SNHG6/miR-944, PCAT6/miR-139-3p, lncRNA-m433s1/miR-433, TUG1/miR-187-3p, SNHG1/miR-187-3p, SNHG1/miR-302, SNHG1/miR-372, SNHG1/miR-373, and SNHG1/miR-520 are identified lncRNA/miRNA pairs that are involved in this process. Hsa_circ_0001368 and circOMA1 are two examples of circRNAs that contribute to the pathogenesis of pituitary gland tumors. Meanwhile, SNHG1, LINC00702, LINC00460, and MEG3 have been found to partake in the pathogenesis of meningioma. In the current review, we describe the role of non-coding RNAs in two types of brain tumors, i.e., pituitary tumors and meningioma.

MicroRNA-137 Inhibited Hypoxia-Induced Proliferation of Pulmonary Artery Smooth Muscle Cells by Targeting Calpain-2

The proliferation of pulmonary artery smooth muscle cells (PASMCs) is an important cause of pulmonary vascular remodeling in pulmonary hypertension (PH). It has been reported that miR-137 inhibits the proliferation of tumor cells. However, whether miR-137 is involved in PH remains unclear. In this study, male Sprague-Dawley rats were subjected to 10% O₂ for 3 weeks to establish PH, and rat primary PASMCs were treated with hypoxia (3% O₂) for 48 h to induce cell proliferation. The effect of miR-137 on PASMC proliferation and calpain-2 expression was assessed by transfecting miR-137 mimic and inhibitor. The effect of calpain-2 on PASMC proliferation was assessed by transfecting calpain-2 siRNA. The present study found for the first time that miR-137 was downregulated in pulmonary arteries of hypoxic PH rats and in hypoxia-treated PASMCs. miR-137 mimic inhibited hypoxia-induced PASMC proliferation and upregulation of calpain-2 expression in PASMCs. Furthermore, miR-137 inhibitor induced the proliferation of PASMCs under normoxia, and knockdown of calpain-2 mRNA by siRNA significantly inhibited hypoxia-induced proliferation of PASMCs. Our study demonstrated that hypoxia-induced downregulation of miR-137 expression promoted the proliferation of PASMCs by targeting calpain-2, thereby potentially resulting in pulmonary vascular remodeling in hypoxic PH.

MicroRNAs as Potential Biomarkers in Pituitary Adenomas

Pituitary adenomas (PAs) are one of the most common lesions of intracranial neoplasms, occurring in approximately 15% of the general population. They are typically benign, although some adenomas show aggressive behavior, exhibiting rapid growth, drug resistance, and invasion of surrounding tissues. Despite ongoing improvements in diagnostic and therapeutic strategies, late first diagnosis is common, and patients with PAs are prone to relapse. Therefore, earlier diagnosis and prevention of recurrence are of importance to improve patient care. MicroRNAs (miRNAs) are short non-coding single stranded RNAs that regulate gene expression at the post-transcriptional level. An increasing number of studies indicate that a deregulation of their expression patterns is related with pituitary tumorigenesis, suggesting that these small molecules could play a critical role in contributing to tumorigenesis and the onset of these tumors by acting either as oncosuppressors or as oncogenes, depending on the biological context. This paper provides an overview of miRNAs involved in PA tumorigenesis, which might serve as novel potential diagnostic and prognostic non-invasive biomarkers, and for the future development of miRNA-based therapeutic strategies for PAs.

Serum miR-137 serves as a novel biomarker for cerebral atherosclerosis diagnosis and cerebrovascular event prediction

MicroRNAs have been reported as biomarkers for various diseases, including cerebral atherosclerosis (AS). In this study, whether serum microRNA-137 (miR-137) could be used as a biomarker for diagnosing cerebral AS and predicting cerebrovascular event was investigated. Quantitative real-time PCR was used to measure the expression of miR-137 in serum. Logistic analysis was used to evaluate the risk factors for the occurrence of cerebral AS, and receiver operating characteristic curves were used to estimate the diagnostic value of miR-137 and other risk factors for AS occurrence. Furthermore, the prognostic value of miR-137 for patients with AS was estimated using Kaplan–Meier survival analysis and Cox regression analysis. The results indicated that serum miR-137 levels were decreased in patients with cerebral AS. The expression of miR-137 was negatively correlated with total cholesterol and low-density lipoprotein cholesterol levels in patients with cerebral AS. The levels of miR-137, total cholesterol, low-density lipoprotein cholesterol, and hypersensitivity C response protein may serve as risk factors for the occurrence of cerebral AS, and miR-137 had diagnostic value for AS screening. Cerebral AS patients with positive cerebrovascular events have low miR-137 expression. Patients with high miR-137 expression had a lower incidence of cerebrovascular adverse events (log-rank P = 0.013), and miR-137 was an independent prognostic marker for the prediction of cerebrovascular event occurrence in patients with cerebral AS. In conclusions, our findings indicate that serum miR-137 levels are decreased in patients with cerebral AS and may be a new biomarker for diagnosing cerebral AS and predicting cerebrovascular events.

MicroRNA‑29‑3p regulates the β‑catenin pathway by targeting IGF1 to inhibit the proliferation of prolactinoma cells

The present study aimed to analyze the effects and underlying mechanisms of microRNA (miR)-29-3p on the proliferation and secretory abilities of prolactinoma cells by targeting insulin-like growth factor (IGF)-1/β-catenin. The relationship between miR-29a-3p and the survival of prolactinoma cells was analyzed with the Kaplan-Meier method in reference to The Cancer Genome Atlas. The expression levels of miR-29a-3p and IGF-1 in MMQ and GH3 cells were detected. A dual-luciferase reporter gene assay was performed to verify the combination of miR-29a-3p and IGF-1. Cells were transfected with a miR-29a-3p mimic and/or IGF-1 pcDNA3.1 to analyze the effects on the proliferation, apoptosis and secretion of prolactin (PRL) and growth hormone (GH) of prolactinoma cells. The effects on β-catenin in the cytoplasm and nucleus were investigated by western blot analysis. The results showed that miR-29a-3p expression was low in MMQ and GH3 cells. Overexpression miR-29a-3p inhibited IGF-1 mRNA and protein expression. miR-29a-3p inhibited cell proliferation and PRL and GH expression, and promoted apoptosis by inhibiting IGF-1. Increasing the expression of miR-29a-3p increased β-catenin levels in the cytoplasm, whereas IGF-1 promoted β-catenin activation and entry into the nucleus, and reversed the inhibitory effects of miR-29a-3p on β-catenin. To conclude, miR-29a-3p inhibited the proliferation and secretory abilities of prolactinoma cells by inhibiting nuclear translocation of β-catenin via a molecular mechanism that is inseparable from IGF-1.

Comparative Proteomic Study Shows the Expression of Hint-1 in Pituitary Adenomas

Pituitary adenomas (PAs) can be unpredictable and aggressive tumors. No reliable markers of their biological behavior have been found. Here, a proteomic analysis was applied to identify proteins in the expression profile between invasive and non-invasive PAs to search for possible biomarkers. A histopathological and immunohistochemical (adenohypophyseal hormones, Ki-67, p53, CD34, VEGF, Flk1 antibodies) analysis was done; a proteomic map was evaluated in 64 out of 128 tumors. There were 107 (84%) invasive and 21 (16%) non-invasive PAs; 80.5% belonged to III and IV grades of the Hardy–Vezina classification. Invasive PAs (n = 56) showed 105 ± 43 spots; 86 ± 32 spots in non-invasive PAs (n = 8) were observed. The 13 most prominent spots were selected and 11 proteins related to neoplastic process in different types of tumors were identified. Hint1 (Histidine triad nucleotide-binding protein 1) high expression in invasive PA was found (11.8 ± 1.4, p = 0.005), especially at high index (>10; p = 0.0002). High Hint1 expression was found in invasive VEGF positive PA (13.8 ± 2.3, p = 0.005) and in Flk1 positive PA (14.04 ± 2.28, p = 0.006). Hint1 is related to human tumorigenesis by its interaction with signaling pathways and transcription factors. It could be related to invasive behavior in PAs. This is the first report on Hint expression in PAs. More analysis is needed to find out the possible role of Hint in these tumors.

Dysregulated miR-137 and its target EGFR contribute to the progression of pituitary adenomas

Pituitary adenomas (PAs) hypersecrete hormones or cause mass effect symptoms, with 10%-35% patients showing resistance to standard therapies. Targeting epidermal growth factor receptor (EGFR) has significantly improved the clinical outcome in many cancers. In this study, immunochemistry results showed that EGFR associated H-scores in 116 PA samples were higher than those in pituitary glands, and that p21, p27-and Wif-1 associated H-scores were lower (P < 0.05 for all). Patients with high levels of EGFR had increased PA invasion, lower total resection, and lower p21 and p27 expression than those with low levels of EGFR expression. Dual-luciferase reporter gene assays showed that EGFR was the target gene of miR-137, and miR-137 mimic could inhibit the cell proliferation of GH3 cells and induce apoptosis and G1-phase arrest of GH3 cells. A combination of miR-137 mimic and AZD9291 had stronger inhibition on GH3 cells compared with miR-137 mimic or AZD9291 alone; furthermore, miR-137 inhibitor partially reversed the inhibition of AZD9291. p21 and p27 were shown to be involved in the miR-137- and AZD9291-mediated effects on GH3 cells. In all, activation of EGFR in PAs was related to tumor invasive behavior, which reduced the total resection of PAs in patients. A combination of miR-137 and AZD9291 provided a potential treatment for PAs, especially for patients who show resistance to standard treatment.