MGMT promoter methylation and 1p/19q co-deletion of surgically resected pulmonary carcinoid and large-cell neuroendocrine carcinoma

Cytopathology and clinicopathological correlation of renal neuroendocrine neoplasms

INTRODUCTION

There is a lack of documentation regarding cytopathology of renal neuroendocrine neoplasms (NENs) due to their rarity.

MATERIALS AND METHODS

Five cytology cases were gathered from 3 institutes.

RESULTS

Cohort consisted of 4 females and 1 male. Fine needle aspiration biopsy and touch preparation slides of core needle biopsy revealed cellular samples, composed of round, plasmacytoid, or columnar cells. Tumor cells were present in nested, acinar, 3D cluster, and individual cell patterns. Tumor cells in 3 cases exhibited uniformly round to oval small nuclei with inconspicuous nucleoli, finely granular chromatin, and smooth nuclear membranes, whereas 2 other cases showed pleomorphic nuclei with conspicuous nucleoli, nuclear molding, and irregular nuclear membranes. Tumor cells displayed pale or granular cytoplasm, with 1 case showing small vacuoles. Examination of cores and cell blocks demonstrated tumor cells in sheets, nests, or acini. All tumor cells were positive for neuroendocrine immunomarkers. Based on mitotic count, Ki-67 index and morphology, 3 tumors were graded as well-differentiated neuroendocrine tumor (WDNET) (1 grade [G] 3, 1 G2, 1 G1) and 2 as large cell neuroendocrine carcinoma. Deletion of 7q, 10q, and 19q was detected in WDNETs. Two patients with large cell neuroendocrine carcinoma and 1 with WDNET G3 underwent chemotherapy due to aggressiveness, whereas nephrectomy was performed for patients with WDNET G1 and 2 without metastasis.

CONCLUSIONS

Cytopathological characteristics of renal NENs closely resemble those affecting other organs. Despite its rarity, renal NENs should be kept in mind when confronted with morphological resemblances to NENs, to prevent misdiagnosis and inappropriate therapeutic interventions.

Are anaplastic lymphoma kinase (ALK) and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation driver biomarkers of pulmonary neuroendocrine tumors (NETs) and carcinomas (NECs)?

Background: Novel targets in neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) are needed to improve outcome. The presence of O6-Methylguanine-DNA methyltransferase (MGMT) promoter methylation in NETs and NECs may act as a predictive marker for response on treatment with temozolomide. As anaplastic lymphoma kinase (ALK) plays an important role in the nervous system we hypothesized that ALK rearrangement can act as a biomarker in patients with NETs and NECs.

Materials and Methods: We performed a retrospective analysis to establish the frequency of MGMT promoter methylation and ALK expression in tissue samples of patients with NETs and NECs.

Results: 21% (14/67) of patients tested positive for MGMT promoter methylation. MGMT promoter methylation was present in 33% (3/9) patients with typical carcinoid, in 22% (2/9) patients with atypical carcinoid, in 22% (8/37) patients with small cell lung cancer and in 8% (1/12) patient with large cell neuroendocrine carcinoma. ALK- expression was present in 14% (10 of 70 patients). In all of these patients, no ALK-rearrangement nor ALK-mutation was revealed.

Conclusions: Routine testing of NET and NEC samples for an ALK rearrangement is not recommended as ALK-expression is not associated with an ALK-rearrangement. Routine testing of NET and NEC samples for MGMT will detect a promoter hypermethylation in a sizable minority of patients who are eligible for a targeted treatment with temozolomide.

Pan-cancer analysis of m5C regulator genes reveals consistent epigenetic landscape changes in multiple cancers

BACKGROUND

5-Methylcytosine (m5C) is a reversible modification to both DNA and various cellular RNAs. However, its roles in developing human cancers are poorly understood, including the effects of mutant m5C regulators and the outcomes of modified nucleobases in RNAs.

METHODS

Based on The Cancer Genome Atlas (TCGA) database, we uncovered that mutations and copy number variations (CNVs) of m5C regulatory genes were significantly correlated across many cancer types. We then assessed the correlation between the expression of individual m5C regulators and the activity of related hallmark pathways of cancers.

RESULTS

After validating m5C regulators' expression based on their contributions to cancer development and progression, we observed their upregulation within tumor-specific processes. Notably, our research connected aberrant alterations to m5C regulatory genes with poor clinical outcomes among various tumors that may drive cancer pathogenesis and/or survival.

CONCLUSION

Our results offered strong evidence and clinical implications for the involvement of m5C regulators.

Multiple Assays to Determine Methylguanine-Methyltransferase Status in Lung Carcinoids and Correlation with Clinical and Pathological Features

BACKGROUND

O6-methylguanine-methyltransferase (MGMT) is a key enzyme for the DNA repair machinery strongly associated with response to alkylating agents in different tumors. Data on its expression and related clinical impact in neuroendocrine tumors are limited to the gastro-entero-pancreatic system, with controversial results in terms of prognostic or predictive value. In lung carcinoids, although clinical efficacy of alkylating agents has been shown in small studies, very few data to date are available on MGMT status.

OBJECTIVE

To assess MGMT status in lung carcinoids using multiple assays and to compare data with major clinical and pathological features.

METHODS

A retrospective series of 95 lung carcinoids and 51 control cases of high-grade neuroendocrine lung carcinomas was analyzed for MGMT promoter methylation, MGMT gene expression, and MGMT protein expression using pyrosequencing, quantitative real-time PCR, and immunohistochemistry, respectively.

RESULTS

MGMT protein expression was inversely correlated with MGMT promoter methylation and positively with MGMT gene expression. MGMT promoter methylation progressively increased from carcinoids to high-grade carcinomas. In the carcinoid group, decreased MGMT gene expression was significantly associated with aggressive features (atypical histotype, grade G2, larger tumor size, higher T stage, and positive nodal status) but not with survival. MGMT promoter methylation was associated with lower stage and negative nodal status.

CONCLUSIONS

Our study investigated MGMT status in a large series of lung carcinoids in the attempt to move forward a rational use of alkylating agents in these tumors. Interestingly, low MGMT gene expression defines a subgroup of lung carcinoids with aggressive features.

Capecitabine and Temozolomide in Patients with Advanced Pulmonary Carcinoid Tumours

BACKGROUND

Temozolomide and capecitabine (CAPTEM) chemotherapy is known to be active in patients with pancreatic neuroendocrine tumours.

OBJECTIVE

This retrospective analysis set out to describe the efficacy and toxicity of CAPTEM in patients with advanced pulmonary carcinoids (PCs).

METHODS

Patients were included with advanced PC who had been treated with a maximum of 6 cycles of oral temozolomide 200 mg/m2 on days 10-14 and capecitabine 750 mg/m2 b.i.d. on days 1-14, repeated every 28 days, -followed by monthly intramuscular injection of octreotide 30 mg long-acting release as maintenance treatment.

RESULTS

Of the 33 patients, all with well-differentiated PC, 61% had atypical carcinoid, 36% had Ki-67 index >10% and 42% had ≥3 organs involved by metastasis. CAPTEM was administered as first-line treatment in 42% of patients, and 17% had received prior somatostatin analogue treatment. Six patients (18%) achieved a partial response, 19 (58%) had stable disease and 8 (24%) developed progressive disease. After a median time of follow-up of 34.8 months, median progression-free survival (PFS) was 9.0 months and median overall survival 30.4 months. Median duration of disease response was 21.7 months and median duration of disease control 9.7 months. Patients with multi-organ metastasis had shorter PFS, but only when treated as second or third line with CAPTEM (p = 0.023).

CONCLUSIONS

CAPTEM induced a modest response and PFS rate, comparable to other studies with temozolomide in patients with advanced PC. The efficacy of CAPTEM should be compared to that of monotherapy with temozolomide in a prospective clinical trial.