Molecular profiling of Asian patients with advanced melanoma receiving check-point inhibitor treatment

Objective

Melanoma is major medical challenge and being able to monitor treatment response is critical. This study aimed to use molecular profiling of Asian patients with advanced melanoma who were receiving treatment with check-point inhibitors (CPIs) to identify novel biomarkers of tumor response.

Methods

Next-generation sequencing (NGS) was performed using tumor specimens collected from 178 Asian patients with metastatic melanoma receiving CPIs. The NGS data and clinical-pathological factors were analyzed for potential genetic biomarkers of tumor response to CPI treatment.

Results

The most common melanoma subtype was acral melanoma (40%), followed by cutaneous melanoma (32%), mucosal melanoma (26%), and others (2%). For calculation of treatment efficacy, 164 of the patients could be evaluated. The overall response rate was 45.7%, of which 41 cases exhibited complete responses (25.0%) and 34 showed partial responses (20.7%). There were no significant differences in tumor responses based on melanoma subtype (P = 0.295). Genetically, NRAS mutations, TP53 mutations, and NF2 deletions were significantly associated with resistance to CPIs (P < 0.05). In contrast, MYC and RPS6KB1 amplifications were associated with responsiveness to CPIs (P < 0.05). Median progression-free survival (PFS) for patients treated with CPIs was 5.9 months (95% CI, 3.8-8.05 months). Univariate analysis identified TP53 and BRAF mutations, NF2 deletions, and BIRC2 amplifications as poor prognostic factors for PFS (P < 0.05).

Conclusions

This study determined the integrated genomic profiles of Asian patients with metastatic melanoma receiving CPIs and identified candidate biomarkers that reflected treatment outcomes.

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The molecular characterization of Asian melanoma patients receiving check-point inhibitors (CPIs) using NGS has not been reported.

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NRAS and TP53 mutations and NF2 deletions were significantly associated with resistance to CPIs.

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MYC and RPS6KB1 amplifications were associated with responsiveness to CPIs.

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TP53 and BRAF mutations, NF2 deletions, and BIRC2 amplifications were poor prognostic factors for progression-free survival.

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This is the largest integrated genomic study to date that identifying novel biomarkers of CPIs in Asian melanoma patients.

Prediction and clinical implications of portal vein/superior mesenteric vein invasion in patients with resected pancreatic head cancer: the significance of preoperative CT parameters

AIM

To determine the preoperative computed tomography (CT) parameters that predict portal vein/superior mesenteric vein (PV-SMV) invasion in patients with pancreatic head cancer, and to assess whether PV-SMV invasion affects patient survival.

MATERIALS AND METHODS

Sixty patients with PV-SMV invasion, and 60 randomly selected patients without it, who had undergone preoperative CT and subsequent surgery for pancreatic head cancer were enrolled. The following CT parameters were evaluated using multivariate logistic regression and receiver operating characteristic analyses to predict vessel invasion (tumour size and margin, length of involved vessel, distance from the tumour to the vessel, vessel irregularity, the teardrop sign, and tumour-vein interface [TVI]). The Cox proportional hazard model was used to evaluate the effects of PV-SMV invasion on survival.

RESULTS

In multivariate analysis, tumour size (odds ratio [OR]=1.99) and TVI (OR=3.79 [≤90°], 20.66 [>90°, ≤180°], and 47.24 [>180°]) were independent CT predictors of PV-SMV invasion (p<0.05); they achieved a sensitivity of 87%, a specificity of 75%, and an accuracy of 81%; however, PV-SMV invasion did not affect patient survival after surgery (p=0.374).

CONCLUSION

In patients with pancreatic head cancer, preoperative CT parameters can predict PV-SMV invasion with high accuracy. PV-SMV invasion did not affect treatment outcome after surgery.

Emergence of CTNNB1 mutation at acquired resistance to KIT inhibitor in metastatic melanoma

PURPOSE

The KIT inhibitor, imatinib, has shown promising efficacy in patients with KIT-mutated melanoma; however, acquisition of resistance to imatinib occurs rapidly in the majority of patients. The mechanisms of acquired resistance to imatinib in melanoma remain unclear.

METHODS

We analyzed biopsy samples from paired baseline and post-treatment tumor lesions in one patient with KIT-mutated melanoma who had had an initial objective tumor regression in response to imatinib treatment followed by disease progression 8 months later.

RESULTS

Targeted deep sequencing from post-treatment biopsy samples detected an additional mutation in CTNNB1 (S33C) with original KIT L576P mutation. We examined the functional role of the additional CTNNB1 S33C mutation in resistance to imatinib indirectly using the Ba/F3 cell model. Ba/F3 cell lines transfected with both the L576P KIT mutation and the CTNNB1 S33C mutation demonstrated no growth inhibition despite imatinib treatment, whereas growth inhibition was observed in the Ba/F3 cell line transfected with the L576 KIT mutation alone.

CONCLUSIONS

We report the first identification of the emergence of a CTNNB1 mutation that can confer acquired resistance to imatinib. Further investigation into the causes of acquired resistance to imatinib will be essential to improve the prognosis for patients with KIT-mutated melanoma.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas)

OBJECTIVES

Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality.

DESIGN

Retrospective multinational study including SCN diagnosed between 1990 and 2014.

RESULTS

2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1).

CONCLUSIONS

After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN.

TRIAL REGISTRATION NUMBER

IRB 00006477.

Surgical strategies for non-functioning pancreatic neuroendocrine tumours

BACKGROUND

The purpose of this study was to identify management strategies for non-functioning pancreatic neuroendocrine tumours (NF-PNETs) by analysis of surgical outcomes at a single institution.

METHODS

Archived records of patients with NF-PNETs who underwent surgery between 1994 and 2010 were reviewed.

RESULTS

Among 125 patients, the median tumour size was 2·5 (range 0·15-20·5) cm. Of the 51 NF-PNETs with a diameter of no more than 2 cm, 12 (24 per cent) were diagnosed as carcinoma. Overall 20 patients (16·0 per cent) had metastases to the lymph nodes. The minimum size of the tumour with lymph node metastasis was 1·2 cm. Having a NF-PNET of 2 cm or larger significantly increased the probability of a poorly differentiated carcinoma (P = 0·006), and having a NF-PNET of at least 2·5 cm significantly increased the probability of lymph node metastasis (P = 0·048). The 5-year cumulative survival rate after curative resection was 89·7 per cent. During a median follow-up of 31·5 months, there were 27 recurrences (23·1 per cent) and 13 disease-specific deaths (11·1 per cent) among the 117 patients who had an R0 resection. All patients who underwent repeat operations were alive without additional recurrence after a mean(s.d.) follow-up of 27·1(18·0) months.

CONCLUSION

Curative surgery should be performed for control of primary NF-PNETs. Lymph node dissection for NF-PNETs of 2·5 cm or larger and at least node sampling for tumours with a diameter of 1 cm or more are recommended. Debulking surgery should be considered for advanced tumours.

Detection of Merkel cell polyomavirus in Merkel cell carcinomas and small cell carcinomas by PCR and immunohistochemistry

Recently, the clonal integration of a new human polyomavirus (Merkel cell polyomavirus or MCPyV) has been reported in Merkel cell carcinoma (MCC). In order to investigate the presence of MCPyV in small cell carcinomas (SCCs) and small round cell tumors (SRCTs), we collected formalin-fixed paraffin-embedded tissue specimens including 14 MCCs, 24 SCCs, 7 Ewing sarcoma/primitive neuroectodermal tumors (ES/PNETs) and 5 neuroblastomas. We also collected specimens of other cancers including 12 malignant melanomas, 10 breast, 10 ovarian and 20 gastric cancers. We used 3 primer sets for which the sequences were previously published (LT1, LT3, and VP1) and 3 newly designed primer sets (LT1-1, LT1-1a, and LT3a). Quantitative real-time PCR was also performed with the LTq primer set. Nested PCR using the LT3a primer set detected more cases of MCPyV infection in MCC. In total, 12 of 14 (85.7%) MCC cases were positive for MCPyV by PCR, which was consistent with published data. Some SCC specimens were also positive for MCPyV (37.5%) by PCR. PCR products from MCC and SCC cases showed premature truncation and frameshift mutation. Furthermore, one case of ES/PNET and one gastric carcinoma showed MCPyV DNA. However, MCPyV DNA and transcript were only detected in MCCs with quantitative real-time PCR analysis. In addition, 11 of 13 (84.6%) MCC cases and 6 of 23 (26.1%) SCC cases showed immunoreactivity with monoclonal antibodies against MCPyV large T-antigen. Considering both PCR and IHC results, MCPyV was detected in all MCCs tested. The presence of MCPyV in all MCC cases tested and in some SCC cases suggests that MCPyV may be involved in the malignant transformation.

Characteristics of cutaneous cytomegalovirus infection in non-acquired immune deficiency syndrome, immunocompromised patients

BACKGROUND

Although cytomegalovirus (CMV) disease is a severe complication among immunocompromised patients, its cutaneous features have not been frequently reported. As herpes simple virus (HSV) infection commonly develops in CMV skin lesions, a study is needed on the pathogenetic role of CMV in cutaneous lesion formation.

OBJECTIVES

The purpose of this study is to characterize the clinical and histopathological features of cutaneous CMV infection and to determine whether CMV plays a true pathogenetic role in cutaneous lesions, or if it is just an innocent bystander during HSV infection among non-AIDS (acquired immune deficiency syndrome), immunocompromised patients.

PATIENTS AND METHODS

A total of nine human immunodeficiency virus-negative patients diagnosed with cutaneous CMV infection from July 1999 to February 2005 at Samsung Medical Center were analysed in terms of their clinical and histopathological characteristics. In addition, we examined for the co-presence of HSV by performing immunohistochemical analysis and polymerase chain reaction.

RESULTS

All the patients were immunocompromised; five had haematological diseases and four were organ transplant recipients. The clinical and histopathological features were similar to those of previous studies of patients with AIDS. Multiple anogenital ulcerations were the most frequent cutaneous presentation (66.7%). Most cytopathic changes were found in the dermis, particularly within the vascular endothelial cells (77.8%) and macrophages (66.7%). However, the association of CMV with concurrent HSV infection was even lower than that seen in patients with AIDS. Only one patient revealed a co-existing cutaneous HSV infection.

CONCLUSIONS

In non-AIDS individuals, the cutaneous lesions from CMV infection showed similar clinical and histopathological features to those of patients with AIDS. However, skin lesions may not be highly associated with HSV, and CMV does seem to contribute to lesion development as a cutaneous manifestation among the CMV infected, non-AIDS, immunocompromised patients.

Arteriovenous malformation of the pancreas in a patient with gastrointestinal bleeding: helical CT findings

Dynamic computed tomographic (CT) findings of arteriovenous malformation (AVM) of the pancreas include strong enhancement or conglomeration of small hypervascular spots in the pancreas and early contrast filling of the portal vein during the arterial phase. We describe a case with pancreatic AVM in which we identified enlarged arterial feeders and draining veins as supportive findings of the diagnosis and ulceration into the pancreatic duct as a possible cause of gastrointestinal bleeding at contrast-enhanced CT.

A novel splice acceptor mutation in the DSPP gene causing dentinogenesis imperfecta type II

The dentin sialophosphoprotein (DSPP) gene (4q21.3) encodes two major noncollagenous dentin matrix proteins: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Defects in the human gene encoding DSPP cause inherited dentin defects, and these defects can be associated with bilateral progressive high-frequency sensorineural hearing loss. Clinically, five different patterns of inherited dentin defects are distinguished and are classified as dentinogenesis imperfecta (DGI) types I, II, and III, and dentin dysplasia types I and II. The genetic basis for this clinical heterogeneity is unknown. Among the 11 members recruited from the studied kindred, five were affected with autosomal dominant DGI type II. The mutation (g.1188C-->G, IVS2-3C-->G) lay in the third from the last nucleotide of intron 2 and changed its sequence from CAG to GAG. The mutation was correlated with the affection status and was absent in 104 unaffected individuals (208 alleles) with the same ethnic and geological background. The proband was in the primary dentition stage and presented with multiple pulp exposures. The occlusal surface of his dental enamel was generally abraded, and the dentin was heavily worn and uniformly shaded brown. The dental pulp chambers appeared originally to be within normal limits without any sign of obliteration, but over time (by age 4), the pulp chambers became partially or completely obliterated. The oldest affected member (age 59) showed mild hearing loss at high-frequency (8 kHz). Permanent dentition was severely affected in the adults, who had advanced dental attrition, premature loss of teeth, and extensive dental reconstruction.

Effect of eccentric load cycling on microleakage of Class V flowable and packable composite resin restorations

Class V composite restorations are subject to the stresses that induce non-carious cervical lesions. This study evaluated the effect of eccentric oblique load on microleakage of restorations. Class V cavities were randomly prepared on the buccal surfaces of 40 recently extracted premolars and restored with composite resin according to manufacturers' directions. Teeth were randomly assigned to one of four treatment groups with 10 teeth per group: (1) flowable resin (Revolution) without load cycling; (2) packable resin (Prodigy Condensable) without load cycling; (3) flowable resin with load cycling (200,000 cycles) and (4) packable resin with load cycling (200,000 cycles). All teeth were then immersed in 2% methylene blue solution for 24 hours after thermocycling (500 cycles). Dye penetration was measured (scores 0-3). The results indicated that adding load cycling significantly increased microleakage (p < 0.05). No significant differences in microleakage were observed for flowable resin vs packable resin. Gingival margins had significantly more microleakage (p < 0.05) than occlusal margins.

In vivo rehardening of enamel eroded by a cola drink

There are many concerns about the erosive effects of acidic beverages. In this study, the effects of Pepsi-Cola (pH 2.41) on bovine enamel and the rehardening effect resulting from intraoral exposure of the teeth were determined by microhardness testing (Vicker's Hardness Number). Bovine enamel specimens (VHN 380.00 +/- 12.74) were immersed in 100 ml of Pepsi-Cola for five minutes and subsequently exposed to human intraoral environment through the use of a removable resin plate. Microhardness testing was performed on specimens after one hour, twenty-four hours and forty-eight hours of exposure to an intraoral environment. The microhardness value was significantly (p < 0.05) reduced by the cola beverage (VHN 262.13 +/- 20.34), and significantly (p < 0.05) increased after intraoral exposure for one hour (VHN 299.75 +/- 26.86) and twenty-four hours (VHN 328.00 +/- 18.70). The difference in the microhardness between the twenty-four-hour group and the forty-eight-hour group (VHN 333.50 +/- 15.13) was not significant (p > 0.05). The microhardness value of the forty-eight-hour group was significantly less than the values recorded during the initial pre-study measurements p < 0.05).

Remineralizing effects of glass ionomer restorations on adjacent interproximal caries

The purpose of this study was to examine the in vitro remineralization of incipient caries lesions on teeth adjacent interproximally to teeth with Class II glass ionomer cement restorations. Sixty-four extracted molars were selected and 1 x 5 mm artificial caries lesions were created at the interproximal contact point. One hundred micrometer sections were obtained at the caries sites, and polarized-light photomicrographs were obtained. The sections were covered with varnish, leaving only the external section site exposed, and were placed back into the original tooth. In another sixty-four molars, Class II cavities were prepared. Equal numbers of preparations were filled with Fuji IX GP, Vitremer, Ketac-Molar, or Z 250. These sixty-four teeth were mounted to have interproximal contact with the adjacent teeth containing the artificial caries lesions. Specimens were placed in closed environments of artificial saliva for one month. After thirty days, the same sections were photographed again under polarized light, and areas of the lesions were quantitated. Decrease in the size of caries lesions indicated the glass ionomers had significantly greater remineralization effects on adjacent caries than the nonfluoridated composite resin (ANOVA p < 0.05). There were no significant differences among the three glass ionomers tested.

Dentin bond strength of packable composites using one-bottle adhesives

PURPOSE

To evaluate the shear bond strength to dentin of packable composites using their respective one-bottle adhesives.

MATERIALS AND METHODS

Human, noncarious extracted permanent molars stored in distilled water were used. Flat buccal and lingual dentin surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into four groups of 8 teeth (16 surfaces) each: Group 1: Gluma Comfort Bond/Solitaire II; Group 2: Bond 1/Alert; Group 3: Prime & Bond NT/Surefil; Group 4: OptiBond Solo/Prodigy Condensable. Group 5: Single Bond/Z250 (control) Cylindrical samples of the materials were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hrs, thermocycled for 500 cycles in distilled water at 6 degrees C and 60 degrees C and sheared with a universal testing machine at a crosshead speed of 0.5 mm/min.

RESULTS

In MPa: Group 1: 24.39 +/- 3.54; Group 2: 28.96 +/- 4.62; Group 3: 30.77 +/- 4.71; Group 4: 30.82 +/- 3.29; Group 5: 24.93 +/- 5.14. ANOVA revealed that Groups 1 and 2 were statistically significantly different from the other groups; there was no statistically significant difference between Groups 2, 3 and 4.

Bronchus-associated lymphoid tissue (BALT) lymphoma of the lung showing mosaic pattern of inhomogeneous attenuation on thin-section CT: a case report

The authors present a case of histologically proven bronchus-associated lymphoid tissue (BALT) lymphoma of the lung in a patient with primary Sjögren's syndrome that manifested on thin-section CT scan as a mosaic pattern of inhomogeneous attenuation due to mixed small airway and infiltrative abnormalities