KRAS mutational analysis and immunohistochemical studies can help distinguish pancreatic metastases from primary lung adenocarcinomas

Diagnostic gastrointestinal markers in primary lung cancer and pulmonary metastases

Histopathological diagnosis of pulmonary tumors is essential for treatment decisions. The distinction between primary lung adenocarcinoma and pulmonary metastasis from the gastrointestinal (GI) tract may be difficult. Therefore, we compared the diagnostic value of several immunohistochemical markers in pulmonary tumors. Tissue microarrays from 629 resected primary lung cancers and 422 resected pulmonary epithelial metastases from various sites (whereof 275 colorectal cancer) were investigated for the immunohistochemical expression of CDH17, GPA33, MUC2, MUC6, SATB2, and SMAD4, for comparison with CDX2, CK20, CK7, and TTF-1. The most sensitive markers for GI origin were GPA33 (positive in 98%, 60%, and 100% of pulmonary metastases from colorectal cancer, pancreatic cancer, and other GI adenocarcinomas, respectively), CDX2 (99/40/100%), and CDH17 (99/0/100%). In comparison, SATB2 and CK20 showed higher specificity, with expression in 5% and 10% of mucinous primary lung adenocarcinomas and both in 0% of TTF-1-negative non-mucinous primary lung adenocarcinomas (25-50% and 5-16%, respectively, for GPA33/CDX2/CDH17). MUC2 was negative in all primary lung cancers, but positive only in less than half of pulmonary metastases from mucinous adenocarcinomas from other organs. Combining six GI markers did not perfectly separate primary lung cancers from pulmonary metastases including subgroups such as mucinous adenocarcinomas or CK7-positive GI tract metastases. This comprehensive comparison suggests that CDH17, GPA33, and SATB2 may be used as equivalent alternatives to CDX2 and CK20. However, no single or combination of markers can categorically distinguish primary lung cancers from metastatic GI tract cancer.

Patho-transcriptomic analysis of invasive mucinous adenocarcinoma of the lung (IMA): comparison with lung adenocarcinoma with signet ring cell features (SRCC)

Background

Invasive mucinous adenocarcinoma (IMA) comprises ∼5% of lung adenocarcinoma. There is no effective therapy for IMA when surgical resection is not possible. IMA is sometimes confused with adenocarcinoma with signet ring cell features (SRCC) pathologically since both adenocarcinomas feature tumor cells with abundant intracellular mucin. The molecular mechanisms by which such mucin-producing lung adenocarcinomas develop remain unknown.

Methods

Using a Visium spatial transcriptomics approach, we analyzed IMA and compared it with SRCC patho-transcriptomically. Combining spatial transcriptomics data with in vitro studies using RNA-seq and ChIP-seq, we assessed downstream targets of transcription factors HNF4A and SPDEF that are highly expressed in IMA and/or SRCC.

Results

Spatial transcriptomics analysis indicated that there are 6 distinct cell clusters in IMA and SRCC. Notably, two clusters (C1 and C3) of mucinous tumor cells exist in both adenocarcinomas albeit at a different ratio. Importantly, a portion of genes (e.g., NKX2-1 , GKN1 , HNF4A and FOXA3 ) are distinctly expressed while some mucous-related genes (e.g., SPDEF and FOXA2 ) are expressed in both adenocarcinomas. We determined that HNF4A induces MUC3A/B and TM4SF4 and that BI 6015, an HNF4A antagonist, suppressed the growth of IMA cells. Using mutant SPDEF that is associated with COVID-19, we also determined that an intact DNA-binding domain of SPDEF is required for SPDEF-mediated induction of mucin genes ( MUC5AC , MUC5B and AGR2 ). Additionally, we found that XMU-MP-1, a SPDEF inhibitor, suppressed the growth of IMA cells.

Conclusion

These results revealed that IMA and SRCC contain heterogenous tumor cell types, some of which are targetable.

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

CONTEXT.—

Immunohistochemistry has become a valuable ancillary tool for the accurate classification of pleuropulmonary and mediastinal neoplasms necessary for therapeutic decisions and predicting prognostic outcome. Diagnostic accuracy has significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

OBJECTIVE.—

To increase the accuracy of diagnosis and classify pleuropulmonary neoplasms through immunohistochemistry.

DATA SOURCES.—

Literature review and the author's research data and personal practice experience.

CONCLUSIONS.—

This review article highlights that appropriately selecting immunohistochemical panels enables pathologists to effectively diagnose most primary pleuropulmonary neoplasms and differentiate primary lung tumors from a variety of metastatic tumors to the lung. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoid potential diagnostic errors.

Current Approach to Undifferentiated Neoplasms, With Focus on New Developments and Novel Immunohistochemical Stains

CONTEXT.—

Workup of the poorly differentiated or undifferentiated tumor remains a significant and challenging entity in the practice of anatomic pathology. Particularly in the setting of small biopsies and limited material, these cases demand a balanced approach that considers the patient's clinical and radiologic presentation, a basic assessment of tumor morphology, a reasonably broad immunohistochemical panel, and diligent preservation of tissue for prognostic and therapeutic studies.

OBJECTIVE.—

To illustrate some of the new and emerging immunohistochemical markers in the evaluation of tumors with undifferentiated or poorly differentiated morphology, with a focus on the workup in limited tissue samples to raise awareness of the issues involved with the pathologic workup in these challenging tumors.

DATA SOURCES.—

A literature review of new ancillary studies that can be applied to cytologic specimens was performed.

CONCLUSIONS.—

Knowledge of the patient's history and communication with the patient's clinical team is essential in formulating a differential diagnosis that can appropriately limit the differential diagnosis based on morphology, especially in small specimens. This information, in conjunction with classifying the tumor morphology (eg, epithelioid, spindled, neuroendocrine, basaloid/biphasic, mixed) gives a logical approach to choosing an initial immunohistochemical panel. Fortunately, immunohistochemistry is evolving quickly in the wake of groundbreaking molecular studies to develop new and better markers to further classify these difficult tumors beyond where we traditionally have been able to go.

Radiomics nomogram for preoperative differentiation of pulmonary mucinous adenocarcinoma from tuberculoma in solitary pulmonary solid nodules

OBJECTIVE

To develop and validate predictive models using clinical parameters, radiomic features and a combination of both for preoperative differentiation of pulmonary nodular mucinous adenocarcinoma (PNMA) from pulmonary tuberculoma (PTB).

METHOD

A total of 124 and 53 patients with PNMA and PTB, respectively, were retrospectively analyzed from January 2017 to November 2022 in The Fourth Affiliated Hospital of Hebei Medical University (Ligang et al., A machine learning model based on CT and clinical features to distinguish pulmonary nodular mucinous adenocarcinoma from tuberculoma, 2023). A total of 1037 radiomic features were extracted from contrast-enhanced computed tomography (CT). The patients were randomly divided into a training group and a test group at a ratio of 7:3. The least absolute shrinkage and selection operator (LASSO) algorithm was used for radiomic feature selection. Three radiomics prediction models were applied: logistic regression (LR), support vector machine (SVM) and random forest (RF). The best performing model was adopted, and the radiomics score (Radscore) was then computed. The clinical model was developed using logistic regression. Finally, a combined model was established based on clinical factors and radiomics features. We externally validated the three models in a group of 68 patients (46 and 22 patients with PNMA and PTB, respectively) from Xing Tai People's Hospital (30 and 14 patients with PNMA and PTB, respectively) and The First Hospital of Xing Tai (16 and 8 patients with PNMA and PTB, respectively). The area under the receiver operating characteristic (ROC) curve (AUC) value and decision curve analysis were used to evaluate the predictive value of the developed models.

RESULTS

The combined model established by the logistic regression method had the best performance. The ROC-AUC (also a decision curve analysis) of the combined model was 0.940, 0.990 and 0.960 in the training group, test group and external validation group, respectively, and the combined model showed good predictive performance for the differentiation of PNMA from PTB. The Brier scores of the combined model were 0.132 and 0.068 in the training group and test group, respectively.

CONCLUSION

The combined model incorporating radiomics features and clinical parameters may have potential value for the preoperative differentiation of PNMA from PTB.

Analysis of KRAS Mutations in Gastrointestinal Tract Adenocarcinomas Reveals Site-Specific Mutational Signatures

Adenocarcinomas of the luminal gastrointestinal tract and pancreatobiliary system often show histologic and immunohistochemical overlap, making delineation of the primary site in a metastatic setting difficult. Previous studies have shown that site-specific missense mutations in the oncogene KRAS could be used in conjunction with immunohistochemistry to differentiate metastatic pancreatic adenocarcinoma from primary lung adenocarcinoma. In this study, we assessed the patterning of KRAS mutations across sites in the gastrointestinal and pancreatobiliary system. By integrating sequencing data from 44 separate studies, we assessed 2523 KRAS mutations in 7382 distinct cases of adenocarcinoma, including those from the esophagus, stomach, ampulla, biliary system, pancreas, and colon. We found that gastrointestinal adenocarcinomas demonstrate a marked regional variation in the frequency of KRAS mutations, with the most frequent KRAS mutation observed in pancreatic adenocarcinoma (up to 94.9%), whereas the frequency is much lower in adenocarcinomas from the esophagus and stomach (5.4% and 8.7%, respectively). Intriguingly, the pattern of missense mutations showed site specificity as well, with c.35G>T (p.G12V) and c.34G>C (p.G12R) mutations enriched in pancreatic primaries and codon 13 and non-codon 12/13 alterations enriched in gastric primaries (specificity of 98.9% and 93.2%, respectively, with a negative predictive value of 93.6% and 92.93% against pancreatic adenocarcinoma). Furthermore, we found that esophageal and gastric adenocarcinomas show an enrichment in transitional mutations, whereas other sites showed an equal distribution. Importantly, the examination of a validation cohort from our own institution revealed similar trends. These findings indicate that, in addition to providing therapeutic and diagnostic information, KRAS mutational analysis may also prove useful in delineating the site of origin in gastrointestinal adenocarcinomas that share morphologic and immunohistochemical overlap. Moreover, transitional mutations are more frequent in esophageal and gastric adenocarcinomas, reiterating the role of chronic inflammation in the pathogenesis of foregut adenocarcinomas.

Malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer

Malignant biliary obstruction generally results from primary malignancies of the pancreatic head, bile duct, gallbladder, liver, and ampulla of Vater. Metastatic lesions from other primaries to these organs or nearby lymph nodes are rarer causes of biliary obstruction. The most common primaries include renal cancer, lung cancer, gastric cancer, colorectal cancer, breast cancer, lymphoma, and melanoma. They may be difficult to differentiate from primary hepato-pancreato-biliary cancer based on imaging studies, or even on biopsy. There is also no consensus on the optimal method of treatment, including the feasibility and effectiveness of endoscopic intervention or surgery. A thorough review of the literature on pancreato-biliary metastases and malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer is presented. The diagnostic modality and clinical characteristics may differ significantly depending on the type of primary cancer. Different primaries also cause malignant biliary obstruction in different ways, including direct invasion, pancreatic or biliary metastasis, hilar lymph node metastasis, liver metastasis, and peritoneal carcinomatosis. Metastasectomy may hold promise for some types of pancreato-biliary metastases. This review aims to elucidate the current knowledge in this area, which has received sparse attention in the past. The aging population, advances in diagnostic imaging, and improved treatment options may lead to an increase in these rare occurrences going forward.

Impact of LBC fixative type and fixation time on molecular analysis of pancreatic cancer cells: A comparative study of cell morphology, antigenicity and nucleic acids

Introduction:

Liquid-based cytology (LBC) has been widely used since 2000. Next-Generation Sequencing (NGS) analysis of residual specimens in LBC fixative may also be performed for pancreatic cancer in the near future. We examined cell morphology, antigenicity and nucleic acids in pancreatic cancer cells at different fixation times using two types of LBC fixatives.

Methods:

PANC-1 cells were fixed in 1 ml CytoRich Red (CR), CytoRich Blue (CB), 95% ethanol (95% AL) or 10% neutral buffered formalin (10% NBF) and evaluated for cell area, antigenicity and nucleic acids with fixation times of 1 hour and 1, 3, 9, and 14 days. Antigenicity was evaluated by immunocytochemical staining for p53 and CK20, and nucleic acid fragmentation was assessed by real-time PCR.

Results:

There was no difference in total cell area between 1 hour and 14 day fixation times for the CR group, but the CB group showed cell contraction with 9 days fixation. In immunocytochemical staining, the CR group showed high p53 and CK20 positivity even after 14 days fixation. The CB group had a lower p53 positive rate than the CR group from 1 hour fixation. For nucleic acid fragmentation, Ct values for the CR group increased with fixation time. The CB group had consistently low Ct values.

Conclusion:

Different LBC fixatives and fixation time can have varying effects on cell morphology, antigenicity and nucleic acids in pancreatic cancer cells. Therefore, fixative type and fixation time should be considered for molecular testing on residual samples in LBC fixatives.

Significance of pulmonary resection in patients with metachronous pulmonary metastasis from pancreatic ductal adenocarcinoma: a retrospective cohort study

Background

Pulmonary metastases from pancreatic ductal adenocarcinoma (PDAC) are relatively rare. Systemic chemotherapy is the first choice of treatment in patients with distant metastases, and the role of metastasectomy is controversial. The aim of the present study was to evaluate the outcome of patients with pulmonary metastases after resection of PDAC and the indications for metastasectomy.

Methods

We retrospectively analysed patients with pulmonary metastases as the first recurrence after resection of primary PDAC between January 2006 and December 2018. Clinical data were obtained from the patients’ medical records. Relapse-free survival (RFS) and overall survival (OS) were analysed using the Kaplan–Meier method, and statistical significance was evaluated by the log-rank test.

Results

Of the 417 patients with resected PDACs, 24 (7.9%) had pulmonary metastases. Six patients (25.0%) underwent pulmonary resection and 18 (75.0%) received systemic chemotherapy and best supportive care. There were no major complications requiring therapeutic intervention after pulmonary resection. The median RFS was 24.0 months (95% CI 10.8–37.2), and the 1-, 3-, and 5-year RFS rates were 66.7%, 33.3%, and 4.2%, respectively. The median OS was 50.0 months (95% CI 15.9–84.1), and the 1-, 3-, and 5-year OS rates were 95.8%, 70.3%, and 46.4%, respectively. All patients with resected pulmonary metastases were alive at the end of the study, whereas the median OS of the patients who did not undergo resection was 37.0 months (95% CI 34.4–39.6). Therefore, patients with resected pulmonary metastases had a significantly better prognosis (p = 0.008).

Conclusions

Pulmonary resection may improve the prognosis in selected patients with pulmonary metastases from PDAC. However, the present study is based on a small number of patients and may include a selection bias; therefore, a multi-institutional prospective study is needed to clarify the indications for pulmonary resection.

Structure of two G-quadruplexes in equilibrium in the KRAS promoter

KRAS is one of the most mutated oncogenes and still considered an undruggable target. An alternative strategy would consist in targeting its gene rather than the protein, specifically the formation of G-quadruplexes (G4) in its promoter. G4 are secondary structures implicated in biological processes, which can be formed among G-rich DNA (or RNA) sequences. Here we have studied the major conformations of the commonly known KRAS 32R, or simply 32R, a 32 residue sequence within the KRAS Nuclease Hypersensitive Element (NHE) region. We have determined the structure of the two major stable conformers that 32R can adopt and which display slow equilibrium (>ms) with each other. By using different biophysical methods, we found that the nucleotides G9, G25, G28 and G32 are particularly implicated in the exchange between these two conformations. We also showed that a triad at the 3' end further stabilizes one of the G4 conformations, while the second conformer remains more flexible and less stable.

Lung recurrence and its therapeutic strategy in patients with pancreatic cancer

BACKGROUND

/Objectives: The lung is a major metastatic site of pancreatic cancer (PC). We aimed to assess the features and prognosis of patients with PC according to the recurrence pattern and the effect of resection of recurrent lung lesion.

METHODS

We enrolled 168 PC patients who had undergone macroscopically curative resection. All resected lung tumors were evaluated immunohistochemically for expressions of thyroid transcription factor-1 (TTF-1) and napsin A.

RESULTS

The most common site of first recurrence was the liver and local site, followed by the lung, peritoneum, and lymph node. Lung recurrence was observed significantly later than was liver recurrence. The median survival time (MST) after recurrence in patients with first recurrence in the lung was significantly longer than MST in patients with first recurrence in the liver (15.2 months vs 5.2 months, p = 0.039). Seven patients with lung recurrence underwent resection of the recurrent lesion. Surgical resection of single metastasis limited to the lung showed favorable overall survival after recurrence (MST = 36.5 months). Patients with single metastasis limited to the lung showed significantly lower value of FDG-PET SUV_max of the primary pancreatic tumor.

CONCLUSIONS

Patients with first recurrence in the lung showed better prognosis than did patients with first recurrence in the liver. Single metastasis limited to the lung could benefit from surgical resection and was significantly associated with lower FDG-PET SUV_max of the primary pancreatic tumor.

Invasive mucinous adenocarcinoma of the lung

Invasive mucinous adenocarcinoma (IMA) is a unique histological subtype of adenocarcinoma. Due to its low incidence rates, survival data for IMA is scarce and often contradictory. The clinical manifestations of IMA are not precise as compared to other adenocarcinomas, with some patients having bronchial mucus overflow. Difference in immunohistochemical expression levels is present in IMA and invasive non-mucinous adenocarcinomas (INMA). Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are more frequent in IMAs, while epidermal growth factor receptor (EGFR) mutations are relatively rare. This makes it distinct from the other more common adenocarcinomas. Neuregulin 1 (NRG1) gene fusions are considered important therapeutic targets for IMA, suggesting that Afatinib may be an effective drug to treat IMA. However, IMA prognosis remains controversial.

[Immunophenotyping of lung tumors : An update]

The WHO Classification of Lung Tumors (2015) established the use of immunohistochemical stainings for resection specimens, however, detailed recommendations had been missing. Now, an international expert panel has summarized key questions for daily routine practice and provided recommendations to assist the community in the appropriate use of immunohistochemistry in this context. This article provides an overview of the most important aspects.

Comparing clinicopathological features and prognosis of primary pulmonary invasive mucinous adenocarcinoma based on computed tomography findings

Objective

To evaluate the relationship between clinicopathologic characteristics and prognosis in patients with invasive mucinous adenocarcinoma (IMA) of the lung.

Methods

A total of 68 patients who underwent surgical resection for primary lung IMA were reviewed during the period of 2009 and 2017. Tumors were classified as solitary-type or pneumonic-type according to the computed tomography (CT) findings. Cox proportional hazards model was used to assess the effects of clinicopathological characteristics on univariate and multivariable analyses of disease-free survival (DFS).

Results

Solitary-type was found in 54 patients, while pneumonic-type was found in 14 patients. The patients’ age varied between 56 and 68 years (patients’ median age was 61 years). Besides, 50 patients had T1/T2 tumor stage (73.5%). Compared with solitary-type, higher T stage, N stage, and pathological stage (P < 0.001) were found in pneumonic-type. Moreover, the survival analysis showed that the pneumonic-type had a significantly poorer DFS compared with solitary-type (P = 0.004). Univariate analysis showed that pneumonic pattern on CT scan, T stage, pathologic stage, and thyroid transcription factor-1 (TTF-1) were significant predictive factors of survival (P = 0.011, 0.014, 0.013, 0.029, respectively). Multivariate analysis further indicated that pneumonic-type was the only independent prognostic factor for poor survival [hazard ratio (HR) = 6.764, 95% confidence interval (CI): 1.563–29.269, P = 0.011].

Conclusions

Based on CT findings, the solitary-type IMA is associated with a lower stage and better prognosis compared with the pneumonic-type IMA.

Best Practices Recommendations for Diagnostic Immunohistochemistry in Lung Cancer

Since the 2015 WHO classification was introduced into clinical practice, immunohistochemistry (IHC) has figured prominently in lung cancer diagnosis. In addition to distinction of small cell versus non-small cell carcinoma, patients' treatment of choice is directly linked to histologic subtypes of non-small cell carcinoma, which pertains to IHC results, particularly for poorly differentiated tumors. The use of IHC has improved diagnostic accuracy in the classification of lung carcinoma, but the interpretation of IHC results remains challenging in some instances. Also, pathologists must be aware of many interpretation pitfalls, and the use of IHC should be efficient to spare the tissue for molecular testing. The International Association for the Study of Lung Cancer Pathology Committee received questions on practical application and interpretation of IHC in lung cancer diagnosis. After discussions in several International Association for the Study of Lung Cancer Pathology Committee meetings, the issues and caveats were summarized in terms of 11 key questions covering common and important diagnostic situations in a daily clinical practice with some relevant challenging queries. The questions cover topics such as the best IHC markers for distinguishing NSCLC subtypes, differences in thyroid transcription factor 1 clones, and the utility of IHC in diagnosing uncommon subtypes of lung cancer and distinguishing primary from metastatic tumors. This article provides answers and explanations for the key questions about the use of IHC in diagnosis of lung carcinoma, representing viewpoints of experts in thoracic pathology that should assist the community in the appropriate use of IHC in diagnostic pathology.

Genomic characterization of patient-derived xenograft models established from fine needle aspirate biopsies of a primary pancreatic ductal adenocarcinoma and from patient-matched metastatic sites

N-of-1 trials target actionable mutations, yet such approaches do not test genomically-informed therapies in patient tumor models prior to patient treatment. To address this, we developed patient-derived xenograft (PDX) models from fine needle aspiration (FNA) biopsies (FNA-PDX) obtained from primary pancreatic ductal adenocarcinoma (PDAC) at the time of diagnosis. Here, we characterize PDX models established from one primary and two metastatic sites of one patient. We identified an activating KRAS G12R mutation among other mutations in these models. In explant cells derived from these PDX tumor models with a KRAS G12R mutation, treatment with inhibitors of CDKs (including CDK9) reduced phosphorylation of a marker of CDK9 activity (phospho-RNAPII CTD Ser2/5) and reduced viability/growth of explant cells derived from PDAC PDX models. Similarly, a CDK inhibitor reduced phospho-RNAPII CTD Ser2/5, increased apoptosis, and inhibited tumor growth in FNA-PDX and patient-matched metastatic-PDX models. In summary, PDX models can be constructed from FNA biopsies of PDAC which in turn can enable genomic characterization and identification of potential therapies.

Utility of KRAS mutational analysis in the preoperative diagnosis of synchronous pancreatic cancer and intrahepatic cholangiocarcinoma: A case report

RATIONALE

It is often challenging to discriminate between intrahepatic cholangiocarcinoma (ICC) and metastatic liver tumors, especially when the hepatic tumor is small and of a mass-forming type.

PATIENT CONCERNS

We report a 69-year-old woman presented at our hospital with a small solid tumor in the head of the pancreas that was previously discovered during a medical checkup.

DIAGNOSES

The patient was diagnosed with synchronous pancreatic cancer and ICC.

INTERVENTIONS

The patient underwent clinical, histological, immunohistological, and KRAS mutational analysis.

OUTCOMES

Computed tomography revealed poorly enhanced small nodules in both the pancreatic head and liver. Biopsies of both nodules revealed adenocarcinoma; however, it was unclear whether the hepatic lesion was a metastasis of the pancreatic tumor or primary ICC. KRAS mutational analysis from FFPE biopsy samples revealed a discordance of mutation status between the tumors. Therefore, the patient was diagnosed with synchronous pancreatic cancer and ICC, whereupon she underwent hepatopancreatoduodenectomy.

LESSONS

KRAS mutational analysis of FFPE biopsy samples can be utilized for differentiating between ICC and metastatic liver tumor.

Screening for Pancreatic Cancer: Current Status and Future Directions

Pancreatic ductal adenocarcinoma is a lethal disease for a multitude of reasons, including difficulty of early detection, early metastatic spread, and absence of more effective therapies. Even with the advent of newer systemic therapies, the 1-year survival for metastatic disease ranges from 17–23% and 5-year survival is <5%. This necessitates an urgent need for the development of more effective modalities for early detection, particularly due to the long latent period between the genomic cellular changes and the development of metastatic disease. Currently available biochemical and molecular markers have significant potential; however, they require further clinical validation. Endoscopic ultrasound is one of the most sensitive modalities used to both screen and sample lesions, but is limited to use in high-risk patients due to its invasive nature and associated risks. Although clinically meaningful progress has been made in screening the high-risk cohorts in terms of detection of pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasms, and mucinous cystic neoplasms, leading to early diagnosis and treatment, nonselective population-based screening is not yet available for widespread use. Currently there is no consensus on the most appropriate screening protocol for early pancreatic cancer detection. In this review, we focus on understanding the potential role of molecular and radiogenomic markers in the early detection of pancreatic cancer.

Biology of invasive mucinous adenocarcinoma of the lung

Invasive mucinous adenocarcinoma (IMA) is a unique histologic subtype of lung adenocarcinoma. Recent studies document distinctive genetic alterations (e.g., NRG1 fusions) and a "mucinous gene signature" in IMAs, as well as differences in clinical responses to traditional chemotherapies in IMAs versus non-mucinous adenocarcinomas. Our understanding of the genetic and clinical characteristics of IMAs has expanded, confirming the uniqueness of IMAs. Accordingly, IMAs require different therapeutic approaches than do lung adenocarcinomas in general. Here, we review recent updates on the genetic and clinical profiles of IMA of the lung.

Synchronous primary adenocarcinoma of the lung and pancreas: a case series and review of the literature

Aim

The frequency of pancreatic cancer in association with cancer of other organs ranges from 1 to 20%, with the most common ones being gastric, colon, thyroid and genitourinary. The presence of synchronous lung and pancreatic cancers is extremely rare.

Case series

Two patients with extensive smoking history and variable presentations were found to have simultaneous lung and pancreatic masses both lesions being different histologically and on immunohistochemical staining. After individualized treatment plans, the first patient remains free of disease and the second patient is being treated with a palliative intent.

Conclusion

The early recognition and treatment is important as there exists a significant survival difference in patients who have synchronous primaries as opposed to those with metastatic pancreatic adenocarcinoma.

Clinical diagnosis and detection of genetic mutations of pancreatic metastases: A report of four cases and review of the literature

The present study aimed to report our clinical experience regarding the diagnosis and detection of genetic mutations of pancreatic metastases, and to review the relevant literature to expand knowledge of this disease. A total of 4 cases involving pancreatic metastases, which were treated at The First Affiliated Hospital of Soochow University between January 2013 and July 2016, were retrospectively analyzed. This retrospective study considered the clinicopathological variables of the 4 patients, and compared this data with those from the literature, which was searched using PubMed, EMBASE and the Cochrane Library. All 4 patients with pancreatic metastases were diagnosed by computed tomography (CT) scan and confirmed by pathological staining and immunohistochemistry. Mutation analysis was performed in 3 patients to obtain precise mutation information for guiding and evaluating the use of molecularly targeted drugs. In summary, pancreatic metastases are rare and the majority of pancreatic metastases develop from renal cell carcinoma. Diagnoses of pancreatic metastases predominantly rely on CT, pathology and immunohistochemistry. Detection of mutations has clinical value in auxiliary diagnosis and therapy of pancreatic metastases. Based on mutation information, molecularly targeted drugs may prolong the survival of patients with unresectable pancreatic metastases.

Synchronous mucinous and non-mucinous lung adenocarcinomas with different epidermal growth mutational status

In recent years, the spread of more-sensitive diagnostic methods has resulted in an increase of synchronous multiple primary lung cancer diagnosis. Nevertheless, its occurrence is still rare. Distinction between synchronous lesions from second independent primary tumors is a problem when dealing with multiple lung tumors, particularly if the histological type is the same. We present a case report of a 78-year-old female patient referred to our institution due to pneumonia. A subsequent thoracic computed tomography (CT) was performed showing two suspicious lesions, one in the right upper lobe and the other in the right inferior lobe. The CT-guided transthoracic needle biopsy of both pulmonary lesions revealed two adenocarcinomas, but with a rare combination of distinct morphologic variants, as well as different immunophenotypes and epidermal growth factor receptor (EGFR) gene status. The patient refused surgery and was submitted to stereotactic body radiation therapy (SBRT). She maintained tight follow-up and until now, she has not shown any signs of relapse or metastasis. A multidisciplinary approach with clinical, morphologic and molecular evaluation in multiple lung cancer is important to diagnosis and treatment guidance.

Pulmonary adenocarcinoma with mucin production modulates phenotype according to common genetic traits: a reappraisal of mucinous adenocarcinoma and colloid adenocarcinoma

Whether invasive mucinous adenocarcinoma (IMA) and colloid adenocarcinoma (ICA) of the lung represent separate tumour entities, or simply lie within a spectrum of phenotypic variability, is worth investigating. Fifteen ICA, 12 IMA, 9 ALK‐rearranged adenocarcinomas (ALKA), 8 non‐mucinous KRAS‐mutated adenocarcinomas (KRASA) and 9 mucinous breast adenocarcinomas (MBA) were assessed by immunohistochemistry for alveolar (TTF1, cytoplasmic MUC1), intestinal (CDX‐2, MUC2), gastric (membrane MUC1, MUC6), bronchial (MUC5AC), mesenchymal (vimentin), neuroendocrine (chromogranin A, synaptophysin), sex steroid hormone‐related (oestrogen and progesterone receptors), pan‐mucinous (HNF4A) and pan‐epithelial (keratin 7) lineage biomarkers and by targeted next generation sequencing (TNGS) for 50 recurrently altered cancer genes. Unsupervised clustering analysis using molecular features identified cluster 1 (IMA and ICA), cluster 2 (ALKA and KRASA) and cluster 3 (MBA) (p < 0.0001). Cluster 1 showed four histology‐independent sub‐clusters (S1 to S4) pooled by HFN4A and MUC5AC but diversely reacting for TTF1, MUC1, MUC2, MUC6 and CDX2. Sub‐cluster S1 predominantly featured intestinal‐alveolar, S2 gastrointestinal, S3 gastric and S4 alveolar differentiation. In turn, KRASA and ALKA shared alveolar lineage alongside residual MUC5AC expression, with additional focal CDX2 and diffuse vimentin, respectively. A proximal‐to‐distal scheme extending from terminal (TB) and respiratory (RB) bronchioles to alveolar cells was devised, where S3 originated from distal TB (cellular mucinous adenocarcinoma), S2 from proximal RB (secreting mucinous adenocarcinoma), S1 from intermediate RB (mucin lake‐forming colloid adenocarcinoma), S4 from distal RB (colloid alveolar adenocarcinoma), KRASA from juxta‐alveolar RB (KRAS‐mutated non‐mucinous adenocarcinoma) and ALKA from juxta‐bronchial alveolar cells (ALK‐translocated adenocarcinoma). TNGS analysis showed KRAS, LKB1, TP53, APC and CDKN2A mutation predominance. In conclusion, IMA and ICA are basket categories, which likely originate from distinct domains of stem/progenitor cells spatially distributed along bronchioles upon common molecular features and genetic alterations.

Unique Genetic and Survival Characteristics of Invasive Mucinous Adenocarcinoma of the Lung

INTRODUCTION

Invasive mucinous adenocarcinoma is a unique histologic subtype of lung cancer, and our knowledge of its genetic and clinical characteristics is rapidly evolving. Here, we present next- generation sequencing analysis of nucleotide variant and fusion events along with clinical follow-up in a series of lung mucinous adenocarcinoma.

METHODS

We collected 72 mucinous adenocarcinomas from the United States and Korea. All had been previously assessed for KRAS and EGFR mutations. For KRAS wild-type cases (n = 30), we performed deep targeted next-generation sequencing for gene fusions and nucleotide variants and correlated survival and other clinical features.

RESULTS

As expected, KRAS mutations were the most common alteration found (63% of cases); however, the distribution of nucleotide position alterations was more similar to that observed in gastrointestinal tumors than other lung tumors. Within the KRAS-negative cases, we found numerous potentially targetable gene fusions and mutations, including CD74-NRG1, VAMP2-NRG1, TRIM4-BRAF, TPM3-NTRK1, and EML4-ALK gene fusions and ERBB2, BRAF, and PIK3CA mutations. Unexpectedly, we found only two cases with TP53 mutation, which is much lower than observed in lung adenocarcinomas in general. The overall mutation burden was low in histologically confirmed mucinous adenocarcinomas from the public The Cancer Genome Atlas exome data set, regardless of smoking history, suggesting a link between TP53 status and mutation burden in mucinous tumors. There was no significant difference for recurrence-free survival between stage-matched mucinous and nonmucinous adenocarcinomas. It was notable that all recurrence sites were in the lungs for completely resected cases.

CONCLUSIONS

Our data suggest that mucinous adenocarcinoma is typified by (1) frequent KRAS mutations and a growing list of gene fusions, but rare TP53 mutations, (2) a low mutation burden overall, and (3) a recurrence-free survival similar to stage-matched nonmucinous tumors, with recurrences limited to the lungs.

Variation in KRAS driver substitution distributions between tumor types is determined by both mutation and natural selection

Different tumor types vary greatly in their distribution of driver substitutions. Here, we analyzed how mutation and natural selection contribute to differences in the distribution of KRAS driver substitutions between lung, colon and pancreatic adenocarcinomas. We were able to demonstrate that both differences in mutation and differences in selection drive variation in the distribution of KRAS driver substitutions between tumor types. By accounting for the effects of mutation on the distribution of KRAS driver substitutions, we could identify specific KRAS driver substitutions that are more favored by selection in specific tumor types. Such driver substitutions likely improve fitness most when they occur within the context of the tumor type in which they are preferentially favored. Fitting with this, we found that driver substitutions that are more favored by natural selection in a specific type of tumor tend to associate with worse clinical outcomes specifically in that type of tumor.

nab-Paclitaxel for the treatment of advanced squamous non-small-cell lung cancer: a comprehensive update

Despite advances in the treatment of patients with nonsquamous non-small-cell lung cancer (NSCLC), lung cancer remains a leading cause of death globally. Studies have demonstrated that survival varies according to histological subtype, and, in many cases, patients with squamous NSCLC have a poorer survival rate than those with nonsquamous NSCLC. For patients with squamous NSCLC, platinum-based doublets remain the standard first-line therapy option. This is in part because of the efficacy and safety concerns with some of the approved therapies and is secondary to the observation that many of the mutations targetable with currently approved therapies are rare in patients with squamous NSCLC. Recently, a subset analysis of a completed phase III trial demonstrated that use of nab-paclitaxel with carboplatin led to improved responses in patients with squamous NSCLC compared with solvent-based paclitaxel with carboplatin. In this review, the current experience and evolving role of nab-paclitaxel with carboplatin in the treatment of squamous NSCLC is discussed.

Decreased RGS6 expression is associated with poor prognosis in pancreatic cancer patients

Regulator of G-protein signaling 6 (RGS6), a member of a family of RGS proteins, has been reported to involve in multiple processes during tumor development. However, its role in pancreatic cancer has not been studied yet. In this study, we aimed to investigate the expression of RGS6 in pancreatic cancer and its role in predicting outcomes of patients with pancreatic cancer. We first measured the expression of RGS6 mRNA in 20 cases of tumor tissues and matched adjacent non-tumorous tissues by quantitative real-time PCR and examined RGS6 protein by immunohistochemistry in tissue microarrays containing 90 tumor and 90 paired adjacent non-tumor tissues. Decreased RGS6 mRNA detected in primary tumor, compared with their non-tumor counterparts. In addition, decreased RGS6 protein expression was associated with tumor differentiation (P = 0.027), pT classification (P = 0.034), smoking status (P = 0.041) and a poor survival (P = 0.007). Cox proportional hazards regression modeling analysis revealed that lymph node metastasis (P = 0.001; hazard ratio, 2.347, 95% CI, 1.387-3.972), tumor differentiation (P = 0.015; hazard ratio, 0.505, 95% CI, 0.291-0.876) and RGS6 expression (P = 0.048; hazard ratio, 0.567, 95% CI, 0.324-0.994) were three independent prognostic factors. Taken together, these date demonstrate that RGS6 decreases in tumor tissue and may serve as a novel biomarker for outcomes in pancreatic cancer patients and be a potential therapeutic target potential therapeutic target.