Resistance to osimertinib in advanced EGFR-mutated NSCLC: a prospective study of molecular genotyping on tissue and liquid biopsies.

BACKGROUND: Resistance to osimertinib in advanced EGFR-mutated non-small cell lung cancer (NSCLC) constitutes a significant challenge for clinicians either in terms of molecular diagnosis and subsequent therapeutic implications. METHODS: This is a prospective single-centre study with the primary objective of characterising resistance mechanisms to osimertinib in advanced EGFR-mutated NSCLC patients treated both in first- and in second-line. Next-Generation Sequencing analysis was conducted on paired tissue biopsies and plasma samples. A concordance analysis between tissue and plasma was performed. RESULTS: Sixty-five advanced EGFR-mutated NSCLC patients treated with osimertinib in first- (n = 56) or in second-line (n = 9) were included. We managed to perform tissue and liquid biopsies in 65.5% and 89.7% of patients who experienced osimertinib progression, respectively. Acquired resistance mechanisms were identified in 80% of 25 patients with post-progression samples, with MET amplification (n = 8), EGFR C797S (n = 3), and SCLC transformation (n = 2) the most frequently identified. The mean concordance rates between tissue and plasma for the EGFR activating mutation and for the molecular resistance mechanisms were 87.5% and 22.7%, respectively. CONCLUSIONS: Resistance to osimertinib demonstrated to be highly heterogeneous, with MET amplification the main mechanism. Plasma genotyping is a relevant complementary tool which might integrate tissue analysis for the study of resistance mechanisms.

PD-L1 overexpression induces STAT signaling and promotes the secretion of pro-angiogenic cytokines in non-small cell lung cancer (NSCLC).

BACKGROUND: Monoclonal antibodies (ICI) targeting the immune checkpoint PD-1/PD-L1 alone or in combination with chemotherapy have demonstrated relevant benefits and established new standards of care in first-line treatment for advanced non-oncogene addicted non-small cell lung cancer (NSCLC). However, a relevant percentage of NSCLC patients, even with high PD-L1 expression, did not respond to ICI, highlighting the presence of intracellular resistance mechanisms that could be dependent on high PD-L1 levels. The intracellular signaling induced by PD-L1 in tumor cells and their correlation with angiogenic signaling pathways are not yet fully elucidated. METHODS: The intrinsic role of PD-L1 was initially checked in two PD-L1 overexpressing NSCLC cells by transcriptome profile and kinase array. The correlation of PD-L1 with VEGF, PECAM-1, and angiogenesis was evaluated in a cohort of advanced NSCLC patients. The secreted cytokines involved in tumor angiogenesis were assessed by Luminex assay and their effect on Huvec migration by a non-contact co-culture system. RESULTS: PD-L1 overexpressing cells modulated pathways involved in tumor inflammation and JAK-STAT signaling. In NSCLC patients, PD-L1 expression was correlated with high tumor intra-vasculature. When challenged with PBMC, PD-L1 overexpressing cells produced higher levels of pro-angiogenic factors compared to parental cells, as a consequence of STAT signaling activation. This increased production of cytokines involved in tumor angiogenesis largely stimulated Huvec migration. Finally, the addition of the anti-antiangiogenic agent nintedanib significantly reduced the spread of Huvec cells when exposed to high levels of pro-angiogenic factors. CONCLUSIONS: In this study, we reported that high PD-L1 modulates STAT signaling in the presence of PBMC and induces pro-angiogenic factor secretion. This could enforce the role of PD-L1 as a crucial regulator of the tumor microenvironment stimulating tumor progression, both as an inhibitor of T-cell activity and as a promoter of tumor angiogenesis.

Primary resistance to osimertinib due to SCLC transformation: Issue of T790M determination on liquid re-biopsy.

OBJECTIVES: EGFR T790M mutation is the most common mechanism of resistance to first-/second-generation EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) and could be overcome by third-generation EGFR-TKIs, such as osimertinib. Liquid biopsy, a non-invasive technique used to test the presence of the resistant mutation, may help avoiding tissue re-biopsy. However, analysing only circulating-free DNA, information about other less frequent and coexisting resistance mechanisms may remain unrevealed. MATERIALS AND METHODS: All patients reported in this series participated in the ASTRIS trial, a real world treatment study testing the efficacy of osimertinib (80mg os die) in advanced T790M-positive NSCLC progressed to prior EGFR-TKI. Patients were considered eligible to osimertinib if T790M positive on tissue or plasma samples. In our patients, EGFR molecular testing on blood sample was conducted with digital droplet PCR (ddPCR). RESULTS: We report our experience of five patients treated with osimertinib after T790M detection on liquid biopsy that presented a disease progression at first tumor assessment mediated by SCLC transformation, as evidenced at tissue re-biopsies. All patients showed low ratio T790M/activating mutation in the blood before osimertinib (lower than 0.03). For three patients, EGFR mutational analysis was T790M-negative when re-assessed by using a less sensitive method (therascreen®) on the same liquid biopsy sample analysed by ddPCR before osimertinib therapy. CONCLUSION: Although liquid biopsy is a relevant tool to diagnose T790M presence in NSCLC patients resistant to EGFR-TKI, in case of a low ratio T790M/activating mutation, tissue biopsy should be considered to exclude the presence of SCLC transformation and/or other concomitant resistance mechanisms.

Computed tomography - histology correlations of unusual lung tumors.

A large variety of rare benign and malignant tumors may sporadically affect the lung. Computed tomography (CT) findings of unusual primary lung tumors are often nonspecific. However, there are some rare pulmonary tumors with imaging features overlapping those of other conditions, thus making radiologic diagnosis challenging. The aim of this review was to correlate CT and histopathological features of a variety of unusual lung tumors to better clarify when and to what extent radiological diagnosis is reliable.

A case of Solitary fibrous pleura tumor associated with severe hypoglycemia: the Doege-Potter 's Syndrome.

Solitary fibrous pleura tumor is a rare primary intrathoracic tumor of the pleura. It usually has an indolent clinical course, but sometimes it can have an aggressive behaviour. In 1930 Doege and Potter independently described this neoplasm, presenting with symptoms of hypoglycemia, hence the eponim of Doege-Potter's Syndrome. In this report, we illustrate a case of Doege Potter's Syndrome, treated with complete surgical resection.

Computed tomography-histologic correlations in lung cancer.

The multidisciplinary approach is ideal in the management of patients with lung cancer. Multidisciplinary evaluation strengthens the differential diagnosis of aspecific radiological findings, indeed. Notably, the differential diagnosis of early stage lung cancer is a current challenge of CT imaging because the earlier the detection, the lower the accuracy of radiological features. This is particularly true for the most common subtype of lung cancer, adenocarcinoma, because it shows various radiological features. Such variety is also reflected by the 2011 classification of lung cancer, that likely affected the diagnostic agreement between radiologist and clinician. This review discusses the common issues of lung cancer diagnosis by paired radiological-histologic interpretation of CT findings.

Familial Uncombable Hair Syndrome: Ultrastructural Hair Study and Response to Biotin.

We report a family affected to the fourth generation by uncombable hair syndrome. This syndrome is characterized by unruly, dry, blond hair with a tangled appearance. The family pedigree strongly supports the hypothesis of autosomal dominant inheritance; some members of the family had, apart from uncombable hair, minor signs of atopy and ectodermal dysplasia, such as abnormalities of the nails. The diagnosis was confirmed by means of extensive scanning electron microscopy. A trial with oral biotin 5 mg/day was started on two young patients with excellent results as regards the hair appearance, although scanning electron microscopy did not show structural changes in the hair. After a 2-year-period of follow-up, hair normality was maintained without biotin, while nail fragility still required biotin supplementation for control.

Oncocytic mucoepidermoid carcinoma of a submandibular gland: a case report and review of the literature.

This report describes the first recognized case of oncocytic mucoepidermoid carcinoma of a submandibular gland, and emphasizes the role of immunohistochemical study in the correct diagnosis of this tumour. This is only the second case in which this tumour has appeared as a completely cystic lesion. A review of the literature was carried out to clarify the clinical and pathological features of this rare malignancy.

Detection of human papillomavirus in organs of upper genital tract in women with cervical cancer.

In this study, we evaluated the presence of human papillomavirus (HPV) DNA in organs of the female upper genital tract, using nine hysterectomy and salpingo-oophorectomy specimens affected by HPV-positive invasive cervical carcinomas, to establish if cervical HPV infection can spread to upper tracts of the female genital system. HPV DNA was evaluated by polymerase chain reaction (PCR) in all cervical carcinomas as well as in all tracts of the genital system. Then, these data were compared with the results obtained from PCR study of five other hysterectomy and salpingo-oophorectomy specimens (control cases). The criteria used for selection of the control cases were informed consent of the patients for research at the time of surgery, absence of neoplasms, absence of any anatomic lesion caused by HPV in cervix, and external genitalia. All selected cases were squamous cervical carcinomas. PCR analysis revealed HPV DNA in all cases of cervical carcinoma. The HPV DNA was detected as weak positivity on PCR analysis in other organs of the genital system. However, the distribution of HPV DNA varied in the various cases and in the different tracts of the same hysterectomy and salpingo-oophorectomy specimen. We believe that the HPV DNA, detected as a weakly positive signal, in the upper genital tract of patients who have a cervical squamous carcinoma could be a reflection of a latent HPV infection, as well as a sign of the existence of micrometastases containing HPV DNA, which cannot be detected by conventional histologic techniques.

Metastatic extragenital neoplasms to the uterus: a clinicopathologic study of four cases.

The aim of this study was to elucidate the clinicopathologic features, the differential diagnostic problems, and the prognostic consequences of patients with metastatic extragenital malignancies to uterus. The patients with metastatic extragenital malignancies to the uterus were evaluated. We considered the metastases in non-genital tract organs at diagnosis of primary neoplasm, the distribution of the metastases in the uterus, and the presence of concomitant metastases in other genital and non-genital tract organs. There were four cases of metastatic extragenital malignancies to the uterus. The breast was the most frequent primary site (two cases: 50%). The other two primary tumors were adenocarcinoma of the cecum and malignant melanoma of the skin. The diagnosis was facilitated by clinical history, revealing the previous primary neoplasm, and by specific immunohistochemical study. Almost all the patients died from disseminated disease. Thus, the prognosis of metastatic extragenital malignancies to the uterus alone or simultaneously to the uterus and other organs of the genital tract is poor. Thus, the metastases to the uterus and to other organs of the genital tract can be considered a preterminal event.

Intranodal myofibroblastoma: a case report and review of literature.

Intranodal myofibroblastoma is rare benign spindle cell neoplasm of lymph node, first described in 1989, that can be confused with other spindle cell tumor. Immunohistochemical and ultrastructural analysis are essential for a correct diagnosis. We reported a typical case of intranodal myofibroblastoma in a 72-year-old female, which is, to our knowledge, the 64th case described in literature. Myofibroblastic differentiation of the lesion was revealed by immunohistochemical positivity for smooth-muscle actin and vimentin and negativity for desmin and S100 protein. On ultrastructural examination the neoplasm showed the presence of cytoplasmic myofilaments with dense bodies and attachment plaques or hemidesmosome-like structures. We also review the literature in order to delineate the clinical and pathological features of this rare neoplasm.