PD-L1 quantification across tumor types using the reverse phase protein microarray: implications for precision medicine.

BACKGROUND: Anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-L1) agents are broadly used in first-line and second-line treatment across different tumor types. While immunohistochemistry-based assays are routinely used to assess PD-L1 expression, their clinical utility remains controversial due to the partial predictive value and lack of standardized cut-offs across antibody clones. Using a high throughput immunoassay, the reverse phase protein microarray (RPPA), coupled with a fluorescence-based detection system, this study compared the performance of six anti-PD-L1 antibody clones on 666 tumor samples. METHODS: PD-L1 expression was measured using five antibody clones (22C3, 28-8, CAL10, E1L3N and SP142) and the therapeutic antibody atezolizumab on 222 lung, 71 ovarian, 52 prostate and 267 breast cancers, and 54 metastatic lesions. To capture clinically relevant variables, our cohort included frozen and formalin-fixed paraffin-embedded samples, surgical specimens and core needle biopsies. Pure tumor epithelia were isolated using laser capture microdissection from 602 samples. Correlation coefficients were calculated to assess concordance between antibody clones. For two independent cohorts of patients with lung cancer treated with nivolumab, RPPA-based PD-L1 measurements were examined along with response to treatment. RESULTS: Median-center PD-L1 dynamic ranged from 0.01 to 39.37 across antibody clones. Correlation coefficients between the six antibody clones were heterogeneous (range: -0.48 to 0.95) and below 0.50 in 61% of the comparisons. In nivolumab-treated patients, RPPA-based measurement identified a subgroup of tumors, where low PD-L1 expression equated to lack of response. CONCLUSIONS: Continuous RPPA-based measurements capture a broad dynamic range of PD-L1 expression in human specimens and heterogeneous concordance levels between antibody clones. This high throughput immunoassay can potentially identify subgroups of tumors in which low expression of PD-L1 equates to lack of response to treatment.

Ovarian Clear Cell Carcinoma: From Morphology to Molecular Biology.

Ovarian clear cell carcinoma (oCCC) is a distinctive subtype of ovarian carcinoma, with peculiar genetic and environmental risk factors, precursor lesions, molecular events during oncogenesis, patterns of spread, and response to treatment. Because of low response to chemotherapy and poor prognosis in advanced stages, there is growing interest in investigating the molecular pathways involved in oCCC development, in order to individualize novel/molecular targeted therapies. Until now, the main molecular genetic changes associated with oCCC remain to be identified, and, although several molecular changes have been reported in clear cell tumors, most studies have analyzed a limited number of cases; therefore, the true prevalence of those changes is not known. The present review will present the clinicopathologic features of oCCC, from morphology to molecular biology, discussing the diagnostic and treatment challenges of this intriguing ovarian carcinoma.

Uncommon frame-shift exon 19 EGFR mutations are sensitive to EGFR tyrosine kinase inhibitors in non-small cell lung carcinoma.

Exons 19-21 EGFR activating mutations are predictive biomarkers of response to EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). However, uncommon exon 19 EGFR mutations, due to their low frequency, have an uncertain biological and clinical significance and very little is known about their TKI sensitivity. This study was designed to describe the TKI sensitivity of a small cohort of lung adenocarcinomas bearing uncommon exon 19 mutations and to evaluate in silico the correlation between frame-shift exon 19 mutations and EGFR sequence/structure modification. Among 1168 NSCLCs screened for EGFR mutational status in our Institutions between 2011 and 2016, seven uncommon exon 19 EGFR mutations were further evaluated: five complex mutations, characterized by a deletion followed by a single-nucleotide insertion, a macrodeletion of 25 bp, and a 19 bp duplication. Interestingly, three patients harboring frame-shift mutations (i.e., one complex mutation, the macrodeletion, and the duplication) showed disease stability and considerably long PFS and OS upon TKI therapy. By contrast, three patients with in-frame complex deletions, independently of the mutation starting point, showed poor/lack of response to TKI therapy. In silico structural analysis showed that sensitivity to TKIs correlates with structural changes in the length and conformation of EGFR C-helix in frame-shift mutations. These data suggest that not all uncommon exon 19 EGFR mutations have the same TKI sensitivity and that frame-shift mutations are responsive to TKIs therapy.

MGMT promoter methylation status in Merkel cell carcinoma: in vitro versus invivo.

PURPOSE: Expression of O6-methylguanine-DNA methyltransferase (MGMT) in Merkel cell carcinoma (MCC) is very variable; thus, we tested whether this may be due to differential methylation of the MGMT gene promoter. METHODS: Quantitative analysis of MGMT mRNA and protein expression, as well as MGMT promoter methylation status, was performed in a series of tissue samples of MCC tumors, representing both primary and metastatic lesions, as well as in six MCC cell lines. RESULTS: These analyses revealed a very heterogeneous MGMT mRNA and protein expression in MCC both in vivo and in vitro. However, neither the MGMT mRNA nor protein expression correlated with the sensitivity of MCC cell lines toward the alkylating agent dacarbazine in vitro. Notably, increased methylation at the promoter of the MGMT gene was observed in 2/6 (33%) of the MCC cell lines; however, MGMT promoter methylation was absent in all MCC tissue samples. According to our results, albeit aberrant methylation of MGMT gene promoter can be observed in in vitro propagated MCC cell lines, it seems to be absent or very rare in MCC lesions in situ. CONCLUSION: Thus, the evaluation of this marker has no or only little significance for predicting response to therapy or for improving efficacy of demethylating agents in the treatment of MCC. Microenvironmental factors may play a role in explaining the different results between MCC cell lines and MCC samples.

FOXL2 molecular status in adult granulosa cell tumors of the ovary: A study of primary and metastatic cases.

Granulosa cell tumors (GCTs) of the ovary are uncommon neoplasms, accounting for ~5% of all malignant ovarian tumors. GCTs are a relatively homogeneous group of tumors, categorized into two distinct subtypes, juvenile GCT and adult GCT (AGCT), likely arising from a limited set of molecular events usually involving the disruption of pathways that regulate granulosa cell proliferation. In the present study, the presence of forkheadbox L2 (FOXL2) c.402C>G mutation was investigated in a series of 42 samples of primary and metastatic AGCT of the ovary. The samples consisted of 37 primary and 5 metastatic ovarian AGCTs from 37 patients. FOXL2 mutational status was evaluated using a pyrosequencing approach on 2.5-µm sections of formalin-fixed paraffin-embedded tissue. FOXL2 c.402C>G mutation was found in 33/37 (89.2%) primary AGCTs and in 4/5 (80.0%) metastases, with the molecular status of the metastases recapitulating that of the primary tumors (4 mutated cases and 1 wild-type case). Overall, FOXL2 mutation is present in the majority of primary and metastatic AGCTs, and could be used as a valid tool in the diagnosis of the disease and in cases of metastatic lesions from an unknown primary origin. Moreover the concordance of FOXL2 molecular status in primary and associated metastases suggests its early appearance and genomic stability in AGCT tumorigenesis.

Molecular status of PI3KCA, KRAS and BRAF in ovarian clear cell carcinoma: an analysis of 63 patients.

AIMS: To evaluate the incidence of PI3KCA, KRAS and BRAF mutations in primary ovarian clear cell carcinoma (OCCC). METHODS: 63 consecutive patients, with a proven diagnosis of OCCC, according to WHO criteria, were included into the study. Pyrosequencing analysis of all three genes hotspot regions were performed on 2.5 µm sections of formalin-fixed paraffin-embedded tissue from primary OCCC. RESULTS: PI3KCA mutations were found in 20/63 (32%) cases; KRAS mutations were found in 8/63 (13%); no BRAF V600 mutations were found. In particular, 12/20 mutations (60%) of PI3KCA were found in the exon 20, whereas the remaining eight cases presented mutations in exon 9 (8/20; 40%). KRAS pyrosequencing analysis revealed higher incidence of codon 12 mutations (7/8; 90%) than codon 13 mutations (1/8; 10%). In five cases (5/66; 8%), synchronous mutations, affecting PI3KCA and KRAS genes, were found. No differences were found in the distribution of hotspot mutations, according to the stage. CONCLUSIONS: The high frequency of PI3KCA mutations, the low rate of mutations in KRAS and the absence of mutations in BRAF, indicate a molecular signature of OCCCs different from other ovarian carcinomas. Detection of driver mutations, such as PI3KCA and KRAS, may be the basis for a targeted therapy, although the clinical and therapeutic implications of these findings have to be supported by further studies.

Epidermal growth factor receptor exon 20 p.S768I mutation in non-small cell lung carcinoma: A case report combined with a review of the literature and investigation of clinical significance.

Epidermal growth factor receptor (EGFR) plays a significant role in non-small cell lung cancer (NSCLC), the most prevalent form of lung cancer worldwide. Therefore, EGFR may be a useful molecular target for personalized therapy utilizing tyrosine kinase inhibitors (TKIs). Somatic activating EGFR mutations may be used to identify tumors sensitive to the effects of small-molecule EGFR-TKIs (gefitinib and erlotinib), and alternative, less frequently observed mutations, including the majority of mutations identified within exon 20, may be associated with a lack of response to TKIs. However, due to the comparative rarity of EGFR exon 20 mutations, clinical information concerning the association between EGFR exon 20 mutations and responsiveness to TKIs has been limited within the relevant literature, particularly for certain rare mutations, including p.S768I. The current study reports the case of a patient with NSCLC harboring a p.S768I mutation in the EGFR gene [a substitution at codon 768 of exon 20 (c.2303G>T, p.S768I)], as well as a mutation at codon 719, exon 18 (p.G719A). The relevant literature concerning this rare EGFR somatic mutation is also reviewed.

New developments in the management of advanced melanoma - role of pembrolizumab.

Cancer immunotherapy is now recognized to be fundamental in modern oncology, because immune system recruitment may represent a powerful and innovative strategy in cancer therapy. Pembrolizumab, a highly selective humanized monoclonal antibody directly blocking the interaction between programmed cell death-1 expressed by tumor-associated T-cells and its ligand programmed cell death-L1 present on tumor and stromal cells, was recently approved by US Food and Drug Administration for the treatment of patients with unresectable or metastatic melanoma and disease progression upon ipilimumab and BRAF inhibitor. This review will focus on the clinical development and use of pembrolizumab in the clinical practice and in the management of advanced melanoma.

Oral malignant melanoma: A report of two cases with BRAF molecular analysis.

Primary oral malignant melanoma is a rare condition, accounting for 1.3-1.4% of all melanomas, usually presenting with an aggressive clinical behavior. The present study reports the clinicopathological findings of two cases of oral malignant melanoma and discusses the epidemiology, diagnosis and current therapeutic approaches for this uncommon condition. In the first case the patient presented with a pigmented lesion located on the lower mucosal lip. The patient showed no nodal metastases and therefore, underwent a wedge resection. After seven months, the patient presented with neck lymph nodes and multiple visceral metastases. Molecular analysis of BRAF, using a pyrosequencing approach, revealed the presence of BRAF V600E mutation. The patient developed multiple visceral metastases, but refused treatment and was lost to follow-up. In the second case, no BRAF V600E mutation was found, but the patient exhibited a pigmented patch in the lower gingival mucosa, which was excised by surgical treatment. The patient was followed up by an oncologist, but did not undergo an additional therapy and is currently alive with no evidence of visceral metastases at one year following the diagnosis.

Mutational status of KRAS, NRAS, and BRAF in primary clear cell ovarian carcinoma.

Ovarian clear cell carcinoma (OCCC) is a subtype of epithelial ovarian cancer with characteristic biological features and aggressive clinical behavior. OCCCs show a pattern of gene mutations different from other type I ovarian malignancies, notably a higher frequency of PIK3CA mutations. In low grade serous ovarian cancer, KRAS and BRAF mutations are frequent, but little data are available on the mutational status of these genes in OCCCs. To clarify this issue, we designed a clinicopathological study with the aim to establish the incidence of KRAS, NRAS, and BRAF hot spot mutations in OCCC. Between December 2006 and June 2012, 22 patients with a proven diagnosis of OCCC were admitted to our Institutions. In all cases, final diagnosis was established according to FIGO and WHO criteria. All women received complete surgical staging. The PyroMark Q24 system (Qiagen GmbH, Hilden, Germany) was used for pyrosequencing analysis of KRAS, NRAS, and BRAF hot spot regions on 2.5-µm sections of formalin-fixed paraffin-embedded tissue from primary OCCC. Pyrosequencing analysis of KRAS, NRAS, and BRAF hot spot regions revealed the presence of mutations only at codon 12 in exon 2 of KRAS in 3 of 22 (14 %) cases. We found no mutations in the hot spot regions of NRAF (exons 2, 3, 4) or BRAF (exon 15). The median age of women with a KRAS mutated OCCC was 74 years. These OCCC were unilateral FIGO stage IA lesions in two cases associated with foci of endometriosis. We conclude that in 14 % of OCCCs, a KRAS mutation occurs in codon 2 exon 2. NRAS and BRAF mutations were not found.

Pyrosequencing evaluation of low-frequency KRAS mutant alleles for EGF receptor therapy selection in metastatic colorectal carcinoma.

AIM: To evaluate whether pyrosequencing (PS) improves the KRAS mutational status predictive value. PATIENTS & METHODS: A retrospective analysis of KRAS mutations by PS and direct sequencing (DS) in 192 metastatic colorectal carcinomas (mCRCs), subgrouped in 51 KRAS mutated at PS and 141 KRAS wild-type at DS. RESULTS: DS failed to detect low-frequency KRAS mutations in four out of 51 mCRCs, whereas PS detected 12 additional low-frequency KRAS mutations in 141 mCRCs KRAS wild-type at DS. After reanalyzing by PS 97 KRAS wild-type tumors treated with anti-EGF receptor (EGFR) antibodies, nine additional mutations were revealed in nonresponders, whereas none of responders exhibited a KRAS-mutated genotype. Of note, KRAS-mutated tumors upon PS showed a worst progression-free survival after EGFR therapy. Finally, PS allowed the detection of additional NRAS, BRAF and exon 20 PIK3CA mutations mostly in KRAS wild-type mCRCs resistant to EGFR therapy. CONCLUSION: PS detection of low-frequency mutations may improve the KRAS predictive value for EGFR therapy selection.

PSA nadir and outcome in 100 patients with pT3b prostate cancer.

AIM: The prostate-specific antigen (PSA) nadir and long-term outcome in patients with pT3b prostate cancer were evaluated. PATIENTS AND METHODS: From July 2000 to December 2012, in 100 patients (median age=62 years) with pT3b prostate cancer following radical retropubic prostatectomy (RRP) preoperative and pathological findings predictive of PSA nadir (≤0.2 vs. >0.2 ng/ml) were retrospectively evaluated; moreover, biochemical recurrence-free survival (bRFS), cancer specific survival (CSS) and overall survival (OS) in patients who underwent watchful waiting (16 cases), adjuvant (84 cases) and salvage (10 cases) therapy were recorded. RESULTS: A PSA nadir >0.2 ng/ml was correlated with node involvement, Gleason score ≥9, cT2, PSA >20 ng/ml, positive surgical margins and total cancer percentage >20%. At a median follow-up of 90 months (range=10-155 months) bRFS, OS and CSS were 92%, 96% and 80%, respectively. CONCLUSION: Radical retropubic prostatectomy combined with adjuvant and salvage treatments demonstrated a satisfactory outcome for pT3b prostate cancer.

Prostate needle biopsy: what we do and what should be improved.

Prostate cancer (PCa) is the cancer most frequently diagnosed in older men and the second most frequent for incidence of all tumors. With the widespread use of serum prostate-specific antigen (PSA), the detection rate as well as the incidence of localized tumors has been increasing, thus leading to a drop in PCa-related mortality. However, a corresponding estimated rate of overdiagnosis as high as 50% has been reported, and the adverse side effects related to unnecessary treatments make the overall benefit of PSA mass screening unclear. The lower PSA threshold and extended prostate biopsy protocols have led to a marked increase of small, low-grade tumors that will never threaten a patient's survival. Sextant biopsy technique, extended biopsy protocols (12-18 cores) and saturation prostate schemes are already familiar terms, together with quantitative histology in the pathology departments. This brief review will try to focus on what usually is done and what should be improved in prostate needle biopsy in order to answer many critical points such as the clinical implication of different modalities of prostate biopsy (transrectal, transperineal or even targeted), the use of quantitative histology and the importance of the new molecular findings in addition to conventional histological parameters in the era of the active surveillance protocols.

Biological insights into BRAFV600 mutations in melanoma patient: Not mere therapeutic targets.

Some experimental evidence indicates that uncommon BRAF mutations consisting in the substitution of 2 adjacent nucleotides within codon 600 are in a cis configuration and associate with BRAF gene amplification. These findings suggest that BRAFV600 mutations are unlikely to occur as homozygous alterations in clinical melanoma samples, with gene amplification perhaps contributing to mask the heterozygous state.

Diagnostic consideration for sinonasal Wegener's granulomatosis clinically mistaken for carcinoma.

We report a case of Wegener's granulomatosis clinically mistaken for carcinoma in a 21-year-old girl presenting with an ulcerated mass of the nasopharynx associated with enlarged laterocervical nodes. The lesion was clinically suspected as malignant on the basis of clinical and radiological findings (namely, computed tomography scan and positron emission tomography). However, multiple biopsies were not conclusive for malignancy showing histological change suggestive of Wegener's granulomatosis. A serum determination of cANCA supported the diagnosis of Wegener's granulomatosis. Clinical findings and image studies suggested an erroneous diagnosis of malignancy whereas a definitive diagnosis of Wegener's granulomatosis was achieved only after repeated biopsies thus leading to a correct therapeutic approach. The Wegener granulomatosis must be added to the list of the differential diagnoses of the masses of the nasopharynx associated with or without enlarged laterocervical nodes.

Mechanisms of resistance to EGFR tyrosine kinase inhibitors gefitinib/erlotinib and to ALK inhibitor crizotinib.

The discovery of several molecular alterations that underlie non-small cell lung cancer (NSCLC) pathogenesis has led to the development of targeted therapies. In particular, gefitinib and erlotinib have become the standard of care in patients harboring epidermal growth factor receptor mutations, while crizotinib showed an impressive efficacy in patients with ALK-positive NSCLC. Nevertheless, the occurrence of clinical resistance limits the long term results of these novel agents. The identification of the molecular mechanisms responsible for acquired resistance to targeted therapy is crucial in order to pursue the creation of rational strategies to overcome resistance. In the current review, we will focus on the acquired resistance mechanisms to EGFR-TKIs and crizotinib and the therapeutic strategies currently under study to overcome resistance.

Coexistence of two different mutations in codon 12 of the Kras gene in colorectal cancer: Report of a case supporting the concept of tumoral heterogeneity.

Evaluation of the mutational status of KRAS is a crucial step for the correct therapeutic approach in treating advanced colorectal cancer as the identification of wild-type KRAS tumors leads to more specific and less toxic treatments for patients. Although several studies have highlighted the differences between primary and metastatic tumors, the possibility of two or more mutations in the same codon has seldom been reported. The present study reports an additional case of an advanced adenocarcinoma of the colon showing two somatic mutations (p.G12D and p.G12V) in the same codon (codon 12) of exon 2 of the KRAS gene, thus supporting the possibility of two differing clonal origins of the tumor. Although the clinical significance of multiple mutations remains unknown at present, based on the limited data available in the literature, this rare event appears to be associated with a more aggressive disease, as in the present case. This case report demonstrates the existence of intratumoral heterogeneity and the coexistence of distinct clones within a tumor that may have profound clinical implications for disease progression and therapeutic responses.