Application of INSM1 in Diagnosis and Grading of Laryngeal Neuroendocrine Carcinoma

Comparison of INSM1 immunostaining with established neuroendocrine markers synaptophysin and chromogranin A in over 14,000 neuroendocrine and non-neuroendocrine tumors

INSM1 is a transcription factor protein which is increasingly used as an immunohistochemical marker for neuroendocrine differentiation. To determine the prevalence of INSM1 expression in tumors and its expression pattern in normal tissues, tissue microarrays containing 14,908 samples from 117 different tumor types/subtypes as well as 76 different normal tissues were analyzed by immunohistochemistry. INSM1 was positive in 89.2% of 471 neuroendocrine neoplasms (NEN) and in 3.5% of 11,815 non-neuroendocrine neoplasms that were successfully analyzed. At least an occasional weak INSM1 positivity was observed in 59 different non-neuroendocrine tumor entities, of which 15 entities contained at least one case with strong INSM1 staining. A comparison with synaptophysin and chromogranin A staining revealed that in NEN, synaptophysin showed the highest sensitivity (93.3%), followed by INSM1 (89.2%) and chromogranin A (87.5%). In neuroendocrine carcinomas (NEC), sensitivity was highest for INSM1 (88.0%), followed by synaptophysin (86.5%) and chromogranin A (66.4%). If INSM1 was used as an additional marker, the sensitivity for detecting neuroendocrine differentiation in NEN increased from 96.6% (synaptophysin and chromogranin A) to 97.2% (synaptophysin, chromogranin A and INSM1). Our study shows that INSM1 is a useful additional marker for neuroendocrine differentiation with high sensitivity, particularly in NEC.

Osamura R, Shiomi T, Matsuno A. Analysis of Insulinoma-Associated Protein 1 Expression in Pituitary Neuroendocrine Tumors

Insulinoma-associated protein 1 (INSM1) is a representative diagnostic marker of neuroendocrine neoplasms (NENs); however, it has not yet been used to diagnose pituitary neuroendocrine tumors (PitNETs), according to the 2022 World Health Organization (WHO) classification of pituitary tumors. This study aimed to examine the expression of INSM1 using immunohistochemistry, in the various cell lineages of PitNET classified by hormone secretion and transcription factor expression. INSM1 expression in PitNETs (different subtypes) and normal pituitary tissues was immunohistochemically assessed. The results were interpreted as scores of 0 (negative), 1 (focally positive), or 2 (frankly positive), depending on the proportion of cell staining. Twenty-eight of 35 PitNET cases (80%) showed INSM1 positivity in their nuclei. The staining in each histological subtype of PitNETs was as follows: somatotroph tumors, score 0 = 3/5, score 1 = 1/5, score 2 = 1/5; lactotroph tumors, score 0 = 2/5, score 1 = 1/5, score 2 = 2/5; thyrotroph tumors, score 2 = 5/5; corticotroph tumors: score 1 = 1/9, score 2 = 8/9; gonadotroph tumors, score 0 = 2/10, score 1 = 0/10, score 2 = 8/10; and unclassifiable tumor, score 1 = 1/1. INSM1 expression in most PitNETs was obtained, similar to that in the normal pituitary gland; thus, INSM1 may maintain the characteristics of anterior pituitary cells and pituitary tumors.

Atypical Carcinoid of the Larynx: A Case Report

Neuroendocrine carcinomas are a spectrum of rare and highly heterogeneous malignant tumors. Neuroendocrine carcinomas mainly arise from neuroendocrine cells scattered throughout the body. They mainly occur in the lung and gastrointestinal tract. Atypical carcinoid of the larynx is a rare type of neuroendocrine carcinoma, which is easily misdiagnosed as hemangioma in appearance. We mainly feature the disease to you through the diagnosis and treatment of a case of atypical carcinoid of the larynx.

Clinical Diagnosis and Treatment of Primary Laryngeal Neuroendocrine Carcinoma

OBJECTIVE

This study aims to investigate the clinical diagnosis and treatment characteristics of primary laryngeal neuroendocrine carcinoma.

PATIENTS AND METHODS

A retrospective analysis was performed for the data of 6 patients with primary laryngeal neuroendocrine carcinoma admitted to the Department of Otorhinolaryngology of Dalian Central Hospital from September 2015 to January 2022, all of whom were male patients. And laryngoscopy showed that 4 had a similar appearance to hemangioma, 1 had nodular hyperplasia, and 1 was papilloma-like. The site of onset was located on the laryngeal surface of the epiglottis in 3 cases, situated in the aryepiglottic fold in 2 cases, and the posterior ventricular zone in 1 case. Five patients underwent surgery, including 4 by transoral endoscopic cryogenic plasma radiofrequency mass resection; one underwent a cervical lymph node dissection and supraglottic horizontal hemilaryngectomy. The remaining 1 case was treated in another hospital after the pathological diagnosis was confirmed by biopsy. All patients had no cervical lymph node metastases and were not supplemented with chemoradiotherapy.

RESULTS

The postoperative pathological diagnosis of all 5 patients was neuroendocrine carcinoma. No cancer cells were seen at the margins and base. One patient was lost to follow-up after treatment in another hospitals and the rest were followed up for 6 months to 6 years. One patient had removed laryngeal tumor and epiglottis by a low-temperature plasma radiofrequency ablation, recurrence 1 year after surgery, and no recurrence for 5 years after supraglottic horizontal hemilaryngectomy combined with prophylactic cervical lymph node dissection, no recurrence for the other 4 patients after 6 months to 4 years of follow-up.

CONCLUSION

The common sites of laryngeal neuroendocrine carcinoma are the laryngeal surface of the epiglottis and the aryepiglottic fold. The appearance of the tumor is mainly similar to that of hemangioma. Moreover, a common pathological classification is atypical carcinoid tumors, where early detection and surgical treatment can achieve a good therapeutic effect.

The Complex Histopathological and Immunohistochemical Spectrum of Neuroendocrine Tumors-An Overview of the Latest Classifications

Neuroendocrine neoplasms (NENs) originate from the neuroendocrine cell system, which may either take the shape of organoid cell aggregations or be composed of dispersed cells across various organs. Therefore, these tumors are heterogenous regarding the site of origin, functional status, degree of aggressiveness, and prognosis. When treating patients with neuroendocrine tumors, one of the most significant challenges for physicians is determining the correct tumor grade and thus classifying patients into risk categories. Over the years, the classification of these tumors has changed significantly, often causing confusion due to clinical, molecular, and immunohistochemical variability. This review aims to outline the latest NENs classifications regardless of their site of origin. Thus, an overview of the key histopathological and immunohistochemical characteristics of NENs could pave the way to validate possible predictive and prognostic markers and also guide the therapeutic conduct.

Insulinoma-Associated Protein 1 (INSM1): Diagnostic, Prognostic, and Therapeutic Use in Small Cell Lung Cancer

Small cell lung carcinoma (SCLC) is an aggressive and difficult to treat cancer. Although immunohistochemistry is not mandatory for a SCLC diagnosis, it might be required, especially in small samples. Insulinoma-associated protein 1 (INSM1) is expressed in endocrine and nervous tissues during embryogenesis, generally absent in adults and re-expressed in SCLC and other neuroendocrine neoplasms. Its high specificity propelled its use as diagnostic biomarker and an attractive therapeutic target. Herein, we aim to provide a systematic and critical review on the use of INSM1 for diagnosis, prognostication and the treatment of SCLC. An extensive bibliographic search was conducted in PubMed® focusing on articles published since 2015. According to the literature, INSM1 is a highly sensitive (75–100%) and specific (82–100%) neuroendocrine immunohistochemical marker for SCLC diagnosis. It can be used in histological and cytological samples. Although advantageous, its standalone use is currently not recommended. Studies correlating INSM1 expression and prognosis have disclosed contrasting results, although the expression seemed to entail a worse survival. Targeting INSM1 effectively suppressed SCLC growth either as a suicide gene therapy regulator or as an indirect target of molecular-targeted therapy. INSM1 represents a valuable biomarker for a SCLC diagnosis that additionally offers vast opportunities for the development of new prognostic and therapeutic strategies.