Non-Small Cell Lung Cancer Testing on Reference Specimens: An Italian Multicenter Experience

INTRODUCTION

Biomarker testing is mandatory for the clinical management of patients with advanced non-small cell lung cancer (NSCLC). Myriads of technical platforms are now available for biomarker analysis with differences in terms of multiplexing capability, analytical sensitivity, and turnaround time (TAT). We evaluated the technical performance of the diagnostic workflows of 24 representative Italian institutions performing molecular tests on a series of artificial reference specimens built to mimic routine diagnostic samples.

METHODS

Sample sets of eight slides from cell blocks of artificial reference specimens harboring exon 19 EGFR (epidermal growth factor receptor) p.E746_AT50del, exon 2 KRAS (Kirsten rat sarcoma viral oncogene homologue) p.G12C, ROS1 (c-ros oncogene 1)-unknown gene fusion, and MET (MET proto-oncogene, receptor tyrosine kinase) Δ exon 14 skipping were distributed to each participating institution. Two independent cell block specimens were validated by the University of Naples Federico II before shipment. Methodological and molecular data from reference specimens were annotated.

RESULTS

Overall, a median DNA concentration of 3.3 ng/µL (range 0.1-10.0 ng/µL) and 13.4 ng/µL (range 2.0-45.8 ng/µL) were obtained with automated and manual technical procedures, respectively. RNA concentrations of 5.7 ng/µL (range 0.2-11.9 ng/µL) and 9.3 ng/µL (range 0.5-18.0 ng/µL) were also detected. KRAS exon 2 p.G12C, EGFR exon 19 p.E736_A750del hotspot mutations, and ROS1 aberrant transcripts were identified in all tested cases, whereas 15 out of 16 (93.7%) centers detected MET exon 14 skipping mutation.

CONCLUSIONS

Optimized technical workflows are crucial in the decision-making strategy of patients with NSCLC. Artificial reference specimens enable optimization of diagnostic workflows for predictive molecular analysis in routine clinical practice.

Somatic Deletion in Exon 10 of Aryl Hydrocarbon Receptor Gene in Human GH-Secreting Pituitary Tumors

OBJECTIVE/PURPOSE

The aryl hydrocarbon receptor (AHR) pathway plays a critical role in the biology of Growth Hormone (GH)-secreting pituitary tumor (somatotropinoma). Germline rs2066853 AHR variant was found to be more frequent among acromegaly patients and associated with a more severe disease with larger invasive somatropinoma, and with resistance to somatostatin analogs treatment in patients living in polluted areas. However, no somatic changes in AHR gene have been reported so far in acromegaly patients. On that basis, the aim of the study was to assess at the somatic level the AHR gene status encompassing exon 10 region, also because of the high rate of variants found in this genomic region.

METHODS

A cohort of 13 patients aged 20-76 years with biochemical, clinical and histological diagnosis of somatotropinoma was studied. DNA and RNA from pituitary tumor histological samples have been extracted and analyzed by PCR and direct sequencing for AHR gene variants, and compared with corresponding patients' germline DNA as well as normal pituitary tissue as reference control.

RESULTS

A degenerated letter codes in the region corresponding to AHR exon 10 (c.1239-c.2056) was detected in somatotropinomas-derived DNA but not in that of matched germline and pituitary normal tissue. By multiple PCR and sequencing analysis, we observed amplification only before codon 1246 and after codon 1254, confirming the presence of a tumor-restricted somatic deletion in the 5' upstream region of AHR exon 10. Analysis of PCR-amplified cDNA revealed a wildtype sequence of exon 9 and 10 in normal pituitary tissue, and a wildtype sequence of exon 9 and 10 up to codon 1246 and no sequence after the deletion region (c.1246-c.1254) in 6 out of 9 tumor samples. Patients carrying the germline rs2066853 AHR variant showed no somatic LOH at the corresponding genetic locus.

CONCLUSION

This is the first demonstration of a recurrent somatic deletion in the exon 10 of the AHR gene in somatotropinomas. The functional impact of this genetic finding needs to be clarified.

Misdiagnosis of the Zollinger-Ellison syndrome due to hyperlipidemia

Most authorities feel that diagnosis of the Zollinger-Ellison syndrome is established when the serum gastrin level is greater than 1000 pg/mL (1000 ng/L) in a patient with gastric acid hypersecretion and clinical manifestations consistent with the diagnosis. A patient with recurrent peptic ulcer disease is reported who was thought to have had the Zollinger-Ellison syndrome based on two serum gastrin level measurements greater than 1000 pg/mL (1000 ng/L). Subsequent evaluation revealed the gastrin elevation to be spurious because the sample was hyperlipidemic. Lipemic serum samples may yield falsely elevated serum gastrin determinations as determined by radioimmunoassay.

Pulmonary paragonimiasis: diagnostic value of pleural fluid analysis

Pleural fluid studies showing a glucose value of less than 10 mg/dl, an LDH level greater than 1,000 IU/L, eosinophilia, a high protein value, and low pH are characteristic of paragonimiasis. In a patient with a pleural effusion and compatible clinical, radiologic, and serologic findings, pleural fluid analysis will allow diagnosis with reasonable certainty even in the absence of positive ova studies, and is useful in distinguishing paragonimiasis from tuberculosis.

Acute colonic pseudo-obstruction: a possible role for the colocolonic reflex

In diverse clinical settings, injury or impairment of the peripheral autonomic nervous system may cause acute colonic pseudo-obstruction. The mechanism has remained elusive since Ogilvie's original description. In classic Ogilvie's syndrome, colonic pseudo-obstruction is associated with malignant invasion of the prevertebral ganglia, and may be mediated through the colocolonic reflex, described in a guinea pig model. We have treated three patients with acute colonic pseudo-obstruction due to: 1) malignant invasion of the prevertebral plexus (classic or true Ogilvie's syndrome), 2) clonidine, and 3) herniorrhaphy under epidural anesthesia. In this paper, we discuss the possible role of the colocolonic reflex in the pathophysiology of acute colonic pseudo-obstruction, and the delineation of true Ogilvie's syndrome from the other many causes of acute colonic pseudo-obstruction.