Immunohistochemical algorithm for differentiation of lung adenocarcinoma and squamous cell carcinoma based on large series of whole-tissue sections with validation in small specimens

A critical appraisal of the clinico-radiological, histopathological and immunohistochemical profile of CT-guided and bronchoscopy-guided biopsies in lung lesions

BACKGROUND

Lung biopsies are obtained by bronchoscopy or by percutaneous route under image guidance and usually have limited tissue material. It is quite challenging for a pathologist to make an accurate diagnosis of lung cancer using only a limited panel of immunohistochemical markers and mucin stains as well as spare as much tissue for molecular testing.Molecular testing for specific genetic mutations or biomarkers serves as an adjunct for more rational, targeted treatment regimens.

METHODS

All the consecutive image-guided lung biopsies (both computed tomography [CT] guided and bronchoscopy-guided) for a period of 3 years (2021-2024) were included in the study. The clinicopathological data was compiled from the hospital records, and histopathology and immunohistochemistry (IHC) were analysed critically for all lung carcinomas. Sensitivity, specificity, negative predictive value, positive predictive value and diagnostic accuracy were calculated for IHC markers.

RESULTS

There were 127 lung biopsies (117 bronchoscopic and 10 CT-guided biopsies) comprise of adenocarcinoma (30%), squamous cell carcinoma (25.2%), small-cell carcinoma (13.4%) and poorly differentiated carcinoma (6.3%). The concordance between clinico-radiological and pathological diagnosis was 85%. P40 (22/22 cases) and CK5/6 (10/10) were the most sensitive and specific markers for squamous cell carcinoma, while TTF-1 (35/36) and Napsin A (18/22) were the most sensitive IHC markers for adenocarcinoma. The most sensitive markers for small-cell carcinoma lung were synaptophysin (17/17), CD 56, NSE followed by chromogranin A (11/15).

CONCLUSION

Integrating conventional histopathology with IHC results in accurate diagnosis, thereby avoiding a broad diagnosis of non-small-cell lung carcinoma (NSCLC). Subclassification of NSCLC has significant treatment implications, especially for advanced-stage tumours for which chemotherapy or targeted therapy is being considered. The focus should be on the judicious use of IHC based on histological type because of the limited availability of tissues in bronchoscopic and CT-guided biopsy specimens.

Pulmonary Adenocarcinoma Updates: Histology, Cytology, and Grading

CONTEXT.—

Adenocarcinomas are the most common histologic subtype of lung cancer, and exist within a widely divergent clinical, radiologic, molecular, and histologic spectrum. There is a strong association between histologic patterns and prognosis that served as the basis for a recently described grading system. As the study of molecular pathology rapidly evolves, all targetable mutations so far have been found in adenocarcinomas, thus requiring accurate diagnosis and classification for the triage of molecular alterations and adequate therapy.

OBJECTIVE.—

To discuss the rationale for adenocarcinoma classifications within the 2021 5th edition of the World Health Organization Classification, with a focus on nonmucinous tumors, including tumor grading and biopsy/cytology diagnosis.

DATA SOURCES.—

PubMed search.

CONCLUSIONS.—

A grading system for adenocarcinoma has improved prognostic impact of the classification of pulmonary adenocarcinoma. An accurate diagnosis of adenocarcinoma in small biopsy material is important for tissue triage for molecular studies and ultimately for patient management and treatment.

Impact of Tobacco, Marijuana, and Alcohol Use on Overall Survival in Recurrent Metastatic Head and Neck Cancer Patients Treated With Immune Checkpoint Inhibitors

AIM

The response rates to immune checkpoint inhibitors (ICI) remain low (13%-20%) in metastatic head and neck cancer patients, indicating an urgent need to better understand factors predictive of response to these agents. This study explored the impact of smoking status, marijuana use, and alcohol consumption on treatment outcomes in recurrent-metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) patients treated with ICI.

METHODS

A retrospective analysis was performed on 201 R/M HNSCC patients treated with ICI between January 15th 2016 and April 9th 2020 at a single institution.

RESULTS

Gender: 154 male (77%), 47 female (23%). Median age 61 (IQR: 55-68). ICI drug: pembrolizumab 100 (50%), nivolumab 91 (45%), nivolumab + ipilimumab 10 (5%). Line of therapy: first: 98 (49%), second and beyond: 103 (51%). Tumor site: oropharynx 84 (42%), oral cavity 45 (22%), larynx 26 (13%), other sites 46 (23%). p16 tumor status: negative 132 (66%), positive 69 (34%). Smoking status: former 111 (55%), never 54 (27%), current 36 (18%), median pack-year 18 (IQR: 0-37). Alcohol use: yes 110 (55%), no 91 (54%). Marijuana use: yes 47 (23%), no 154 (77%). Overall response rate: 36 (18%). Median OS: 12 months (95% CI: 9.4-14.8). Tobacco: former (HR: 0.75, 95% CI: 0.50, 1.11), current (HR: 0.58, 95% CI: 0.33, 1.02). Marijuana: yes (HR: 0.93, 95% CI: 0.58, 1.49). Alcohol: yes (HR: 1.04, 95% CI: 0.72, 1.49).

CONCLUSION

In our cohort, smoking status, marijuana use, and alcohol consumption did not have a statistically significant impact on OS in patients with R/M HNSCC treated with ICI.

Neuroanatomical location of lung cancer brain metastases in 234 patients with a focus on cancer subtyping and biomarkers

Brain metastases are frequent in neuropathology practices; however, the literature on their distribution is frequently derived from imaging studies. This work examined metastases of lung cancer to the brain through the lens of pathology specimens. All brain surgical pathology cases accessioned from 2011-2020 were retrieved from a regional laboratory. Specimens were classified by neuroanatomical location, diagnostic category, and diagnosis with a hierarchical free text string-matching algorithm. All reports classified as probable metastasis per algorithm were reviewed by a pathologist. Lung biomarkers and selected immunostains were retrieved with text parsing and reviewed. Among 4,625 cases of brain surgical resection specimens, 854 were classified as probable metastasis by the algorithm. On report review, 538/854 cases were confirmed as metastasis with a known primary site. The 538 cases were from 511 patients and 234/511 patients had lung primaries. Small cell lung cancer lesions were most frequently found in the cerebellum (17/30). Lesions from lung adenocarcinoma (59/164) and non-small cell carcinoma-not otherwise specified (NSCLC-NOS) (15/34) were most commonly found in the frontal lobe. Squamous cell carcinoma lesions were most commonly found in the frontal and occipital lobes (8/27). 72/234 cases were reported as NSCLC-NOS and could be further subclassified using immunostaining (41/72). Lung biomarker data were retrieved in ~38% of cases. PD-L1 positivity was dependent on neuroanatomical distribution (p = 0.04); other examined biomarkers were not. The distribution of lung tumours metastatic to the brain is dependent on the lung cancer subtype (p<0.001). The reporting of histologic subtype could be further optimized in the local environment.

Tenascin-C in the early lung cancer tumor microenvironment promotes progression through integrin αvβ1 and FAK

Pre-cancerous lung lesions are commonly initiated by activating mutations in the RAS pathway, but do not transition to lung adenocarcinomas (LUAD) without additional oncogenic signals. Here, we show that expression of the extracellular matrix protein Tenascin-C (TNC) is increased in and promotes the earliest stages of LUAD development in oncogenic KRAS-driven lung cancer mouse models and in human LUAD. TNC is initially expressed by fibroblasts and its expression extends to tumor cells as the tumor becomes invasive. Genetic deletion of TNC in the mouse models reduces early tumor burden and high-grade pathology and diminishes tumor cell proliferation, invasion, and focal adhesion kinase (FAK) activity. TNC stimulates cultured LUAD tumor cell proliferation and migration through engagement of αv-containing integrins and subsequent FAK activation. Intringuingly, lung injury causes sustained TNC accumulation in mouse lungs, suggesting injury can induce additional TNC signaling for early tumor cell transition to invasive LUAD. Biospecimens from patients with stage I/II LUAD show TNC in regions of FAK activation and an association of TNC with tumor recurrence after primary tumor resection. These results suggest that exogenous insults that elevate TNC in the lung parenchyma interact with tumor-initiating mutations to drive early LUAD progression and local recurrence.

Application of the 5th WHO Guidelines for the Diagnosis of Lung Carcinoma in Small Lung Biopsies in a Tertiary Care Center: Is Insecurity of Pathologists for the Accurate Diagnosis Justified?

BACKGROUND/OBJECTIVES

The diagnosis of lung carcinoma (LC) is currently performed in small biopsies and according to the WHO classification by using limited stains to spare tissue for molecular testing. This procedure, however, often causes diagnostic uncertainty among pathologists.

METHODS

In this retrospective analysis, we compared the diagnosis made by these guidelines in 288 lung biopsies with that using more stains, as retrieved from our archive. We also compared the results of p63 and p40 immunoexpression and investigated the diagnostic role of p53/Rb1.

RESULTS

In our investigation, we reached a definite diagnosis with a mean number of one stain compared with six stains in the original diagnostic procedure, with a 97.3% concordance rate. Only in the case of metastases, a clear advantage is proven in the use of more stains, especially in the absence of clinical information. We also found a comparable utility of p40 and p63 for the diagnosis of squamous cell carcinoma, despite the higher p63 expression in other histological types. Moreover, normal p53/Rb1 expression could be utilized for the exclusion of small-cell LC.

CONCLUSIONS

Our study confirms the diagnostic certainty achieved by the suggestions of the WHO classification and justifies the potential insecurity in the absence of adequate communication with the treating clinician.

Diagnostic and Predictive Immunocytochemistry in Lung Cancer

BACKGROUND

Immunocytochemistry (ICC) is suitable for use on a range of cytology preparations, such as cell blocks, air-dried slides, ethanol-fixed slides, direct smears, cytospins, and liquid-based cytology (LBC) samples. However, it must be standardized against the gold standard of formalin-fixed paraffin-embedded tissues with adequate number of positive and negative controls. The role of ICC in lung cancer is crucial, as most lung cancer specimens are cytology samples. Accurate diagnosis and testing of certain biomarkers rely heavily on both diagnostic and predictive ICC.

SUMMARY

Key ICC markers important in lung cancer include, but are not limited to, diagnostic ICCs such as TTF-1, p40, Napsin A, and p63, as well as predictive ICCs like ALK, ROS-1, PD-L1, and NTRK.

KEY MESSAGES

With proper validation, immunocytochemistry for lung cancer can be effectively performed on direct smears, cytospins, and other specimens, even when resources for preparing cell blocks are unavailable. This is particularly true for diagnostic antibodies, but it is important to exercise caution with predictive ICC. Nonetheless, a low threshold for molecular testing should be maintained. PD-L1 ICC can be challenging and should ideally be performed on formalin-fixed cell blocks or biopsies when available.

BACKGROUND

Immunocytochemistry (ICC) is suitable for use on a range of cytology preparations, such as cell blocks, air-dried slides, ethanol-fixed slides, direct smears, cytospins, and liquid-based cytology (LBC) samples. However, it must be standardized against the gold standard of formalin-fixed paraffin-embedded tissues with adequate number of positive and negative controls. The role of ICC in lung cancer is crucial, as most lung cancer specimens are cytology samples. Accurate diagnosis and testing of certain biomarkers rely heavily on both diagnostic and predictive ICC.

SUMMARY

Key ICC markers important in lung cancer include, but are not limited to, diagnostic ICCs such as TTF-1, p40, Napsin A, and p63, as well as predictive ICCs like ALK, ROS-1, PD-L1, and NTRK.

KEY MESSAGES

With proper validation, immunocytochemistry for lung cancer can be effectively performed on direct smears, cytospins, and other specimens, even when resources for preparing cell blocks are unavailable. This is particularly true for diagnostic antibodies, but it is important to exercise caution with predictive ICC. Nonetheless, a low threshold for molecular testing should be maintained. PD-L1 ICC can be challenging and should ideally be performed on formalin-fixed cell blocks or biopsies when available.

Selective Naked-Eye Detection of Lung Squamous Cell Carcinoma Mediated by lncRNA SOX2OT Targeted Nanoplasmonic Probe

The application of nanobiotechnology in biomolecule detection can provide fast and accurate tests for diagnosing molecular changing-associated diseases. The use of AuNPs-thiolated probe conjugates has long been considered as an alternative method for the detection of specific DNA/RNA targets. Here, we present a colorimetric direct detection method for the SOX2OT transcript, long noncoding RNAs (lncRNAs), by using a poly guanine tail (G12) as a template for in situ synthesis of gold nanoparticles (AuNPs) without any chemical modification or DNA labeling. We have then developed this proposed detection system based on two complementary sequences of long noncoding RNA SOX2OT with an extra strand of poly G12. Using this method, we were able to differentiate lung squamous cell carcinoma from adenocarcinoma samples. Based on this disclosure, this invention provides a simple visual method to detect specific lncRNA sequences without the need for amplifying the target lncRNA and discriminate squamous cell carcinoma from adenocarcinoma samples. Our invention provides a diagnostic kit to detect RNA by means of direct detection (PCR-free) of the lncRNA by in situ synthesis of AuNPs based on two probes with an extra strand of poly G12.

The utility of the lineage specific immunohistochemical stains SATB2, CDX2, and villin, and the mucin glycoproteins MUC2, MUC5AC, and MUC6 to distinguish pulmonary invasive mucinous adenocarcinoma from metastatic colorectal carcinoma

CONTEXT

The lungs are a common site of tumor metastasis. While morphology and immunophenotype can help differentiate primary from metastatic tumors, distinguishing pulmonary invasive mucinous adenocarcinoma (PIMA) from metastatic colorectal adenocarcinoma (CRC) may occasionally be challenging due to overlapping morphological and immunohistochemical features. Lineage-specific markers such as CDX2, TTF-1, and napsin A are helpful with pulmonary non-mucinous adenocarcinoma (PNMA), however they are non-specific and insensitive when applied to PIMA. SATB2 is a newer marker that distinguishes CRC from upper gastrointestinal and pancreaticobiliary tumors; its utility in distinguishing CRC from PIMA has not been fully elucidated.

OBJECTIVE

To evaluate the performance of lineage-specific and mucin glycoprotein immunostains in distinguishing PIMA and CRC.

DESIGN

We stained tissue microarrays comprising 34 PNMA, 31 PIMA, and 32 CRC with CK7, CK20, SATB2, CDX2, villin, TTF-1, napsin A, and gel-forming mucins MUC2, MUC5AC, and MUC6.

RESULTS

PIMA showed significant (>50% of cells) expression of SATB2 (6%), CDX2 (6%), villin (74%), TTF-1 (13%), and napsin A (23%). However, significant CK7 expression was seen in nearly all PIMA (30/31) and none of the metastatic CRC.

CONCLUSION

Our results suggest that CK7 remains one of the most useful markers for distinguishing primary PIMA from metastatic CRC. Expression of the mucin glycoproteins MUC5AC and MUC6 and lack of expression of MUC2 favored a diagnosis of PIMA, but expression of these markers was too heterogeneous to be of clinical utility. To our knowledge this is the only study comparing the immunohistochemical profile of PIMA and metastatic CRC in lung metastasectomy specimens.

Pseudosquamous Adenocarcinoma of the Lung: Clinicopathologic and Immunohistochemical Study of 10 Cases

Pseudosquamous adenocarcinoma of the lung is an unusual morphologic variant of poorly differentiated non-small cell lung carcinoma that superficially resembles a squamous cell carcinoma. We have examined 10 cases of these tumors in 4 women and 6 men, aged 47 to 93 years. The tumors were all peripheral and measured from 1.5 to 5.5 cm. All cases were characterized by solid nests of large polygonal tumor cells containing atypical nuclei with abundant cytoplasm and sharp cell borders, adopting a pavement-like architecture that simulated squamous cell carcinoma. Some cases demonstrated intracytoplasmic hyaline inclusions suggestive of keratinization. The nests of tumor cells often showed central comedo-like areas of necrosis. Intercellular bridges were not seen in any of the cases. The tumors often displayed marked clearing of the cytoplasm enhancing their epidermoid appearance. In 4 cases, the solid pseudosquamous areas were seen to merge with a focal lepidic adenocarcinoma component, and in 1 case, abortive microscopic foci of acinar differentiation were also noted within the tumor. One case showed focal sarcomatoid spindle cell areas. The tumor cells were negative for p40 and CK5/6 and labeled with TTF1 or Napsin-A, confirming an adenocarcinoma phenotype. Clinical follow-up information was available in 8 patients; 6 patients died of their tumors between 6 months to 11 years after diagnosis (mean: 3.1 y). One patient died of complications related to surgery and one patient with a low-stage tumor died at 27 years from other causes. Solid pattern adenocarcinomas can be confused for squamous cell carcinoma and may require immunohistochemistry to determine their true phenotype.

Characterization of Nonsmall Cell Lung Carcinoma in Limited Biopsy Samples and Identifying Optimal Immunohistochemical Marker Combinations in Resource-Constrained Setup: An Institutional Experience

Background  The incorporation of immunohistochemical markers in the analysis of small biopsy samples, as outlined in the fourth edition of the World Health Organization Blue books, represents a noteworthy advancement in the diagnosis of advanced-stage lung carcinoma. This improved the histological classification for poorly differentiated nonsmall cell lung carcinomas (NSCLCs), especially in small biopsy specimens. Despite challenges in obtaining viable cells from diminutive tumor samples, a focused immunohistochemical panel effectively distinguishes histological types in most NSCLC. This preserves tissue for subsequent molecular testing. Material and Methods  This study examined 130 consecutive lung biopsy cases initially diagnosed as NSCLC, including various biopsy types (transbronchial, endobronchial, ultrasound-guided, computed tomography-guided). Carcinomas were categorized based on specific characteristics, such as glands and/or mucin for adenocarcinomas, keratinization and/or intercellular bridges for squamous cell carcinomas, and recognition of poorly differentiated NSCLC. Cases lacking clear morphological attributes underwent reclassification using immunohistochemical markers (TTF1, Napsin A, p63, and p40). Results  TTF1 exhibited superior sensitivity (97.56%) and specificity (96.77%) for adenocarcinoma compared with Napsin A, with sensitivity and specificity at 90.24 and 93.3%, respectively. p63 and p40 demonstrated 100% sensitivity for squamous cell carcinoma, with p40 being more specific than p63 (100% vs. 82.92%). Using TTF1 and p63 as a conventional panel, 87% of cases were subtyped. However, the combination of TTF1 and p40 achieved accurate classification in 94.66% (71/75) of cases, and all four markers allowed subtype identification in 97.2% (73/75) of cases. Conclusion  In a resource-constrained setting, subtyping NSCLC in small biopsy can be effectively accomplished using a minimal panel consisting of TTF1 and p40 immunohistochemical markers.

Unlocking Precise Lung Cancer Detection Through Minimal Panel Immunostaining in Small Biopsy Samples

Introduction Lung cancer diagnosis faces challenges due to morphological heterogeneity and limited biopsy tissue. This study evaluates the efficacy of a minimal panel immunostaining technique using immunohistochemical markers like napsin A, thyroid transcription factor 1 (TTF-1), p63, and synaptophysin to improve the precision of lung carcinoma subclassification. Methods A retrospective analytical study was conducted at the Histopathology Laboratory of Saveetha Medical College and Hospital, Chennai, from January 2018 to February 2024. A total of 64 lung carcinoma cases were analyzed. Inclusion criteria included biopsy samples from lung lesions with a confirmed diagnosis of lung carcinoma based on histomorphological examination, covering all age groups and both genders. Non-carcinomatous lung lesions were excluded. Clinical data were obtained from the Medical Information Archiving Software (MIAS) database and histopathological examination request forms. Under a light microscope, tissue samples were examined after being fixed in formalin, processed, and stained with hematoxylin and eosin (H&E). Additionally, a minimal panel of immunohistochemical markers, including napsin A, TTF-1, p63, and synaptophysin, was used to subclassify lung carcinomas. Results The age group older than 50 years was the most affected, with a higher incidence in males. Histologically, 49% of cases were adenocarcinoma, 42% were squamous cell carcinoma, and 9% were small cell carcinoma. Immunohistochemistry (IHC) results adjusted these proportions to 54.6% adenocarcinoma, 31.2% squamous cell carcinoma, and 14% small cell carcinoma, showing a 5.6% increase in adenocarcinoma cases. The most common adenocarcinoma pattern was mixed, followed by acinar. TTF-1 and napsin A were crucial for identifying adenocarcinoma, while p63 was key for squamous cell carcinoma. Synaptophysin confirmed neuroendocrine differentiation in small cell carcinoma. Conclusion Incorporating a minimal panel of IHC markers significantly enhances the accuracy of lung carcinoma subclassification, addressing diagnostic challenges posed by morphological heterogeneity and limited sample size. This approach supports more precise and efficient clinical care for patients with lung cancer. Further validation in diverse clinical settings is recommended.

Identification of protein signatures for lung cancer subtypes based on BPSO method

The objective of this study was to identify protein biomarkers that can distinguish between LUAD and LUSC, critical for personalized treatment plans. The proteomic profiling data of LUAD and LUSC samples from TCPA database, along with phenotype and survival information from TCGA database were downloaded and preprocessed for analysis. We used BPSO feature selection method and identified 10 candidate protein biomarkers that have better classifying performance, as analyzed by t-SNE and PCA algorithms. To explore the causalities among these proteins and their associations with tumor subtypes, we conducted the PCStable algorithm to construct a regulatory network. Results indicated that 4 proteins, MIG6, CD26, NF2, and INPP4B, were directly linked to the lung cancer subtypes and may be useful in guiding therapeutic decision-making. Besides, spearman correlation, Cox proportional hazard model and Kaplan-Meier curve was employed to validate the biological significance of the candidate proteins. In summary, our study highlights the importance of protein biomarkers in the classification of lung cancer subtypes and the potential of computational methods for identifying key biomarkers and understanding their underlying biological mechanisms.

Himalayan flora: targeting various molecular pathways in lung cancer

The fatal amplification of lung cancer across the globe and the limitations of current treatment strategies emphasize the necessity for substitute therapeutics. The incorporation of phyto-derived components in chemo treatment holds promise in addressing those challenges. Despite the significant progressions in lung cancer therapeutics, the complexities of molecular mechanism and pathways underlying this disease remain inadequately understood, necessitating novel biomarker targeting. The Himalayas, abundant in diverse plant varieties with established chemotherapeutic potential, presents a promising avenue for investigating potential cures for lung carcinoma. The vast diversity of phytocompounds herein can be explored for targeting the disease. This review delves into the multifaceted targets of lung cancer and explores the established phytochemicals with their specific molecular targets. It emphasizes comprehending the intricate pathways that govern effective therapeutic interventions for lung cancer. Through this exploration of Himalayan flora, this review seeks to illuminate potential breakthroughs in lung cancer management using natural compounds. The amalgamation of Himalayan plant-derived compounds with cautiously designed combined therapeutic approaches such as nanocarrier-mediated drug delivery and synergistic therapy offers an opportunity to redefine the boundaries of lung cancer treatment by reducing the drug resistance and side effects and enabling an effective targeted delivery of drugs. Furthermore, additional studies are obligatory to understand the possible derivation of natural compounds used in current lung cancer treatment from plant species within the Himalayan region.

High-grade Serous Carcinoma can Show Squamoid Morphology Mimicking True Squamous Differentiation

Tubo-ovarian high-grade serous carcinoma (HG-SC) and ovarian endometrioid carcinoma (EC) can show overlapping morphologic features, such as glandular and solid patterns. The differential diagnosis of these subtypes is thus sometimes difficult. The existence of "squamous differentiation" tends to lead to a diagnosis of EC rather than HG-SC. We noticed that HG-SC can contain a "squamoid component," but its nature has been poorly investigated. This study was thus established to clarify the nature of this "squamoid component" in HG-SC by investigating its frequency and immunohistochemical features. We reviewed hematoxylin and eosin-stained slides of 237 primary untreated cases of tubo-ovarian HG-SC and identified 16 cases (6.7%) of HG-SC with "squamoid component." An immunohistochemical staining panel (CK5/6, CK14, CK903, p40, p63, WT1, ER, and PgR) was used to analyze all of these 16 cases. We also selected 14 cases of ovarian EC with "squamous differentiation" as a control. The "squamoid component" in HG-SC was completely p40-negative and showed significantly lower expression of CK5/6, CK14, CK903, and p63 than the "squamous differentiation" in EC. The immunophenotype of the "squamoid component" in HG-SC was concordant with the conventional HG-SC component (WT1-positive/ER-positive). Furthermore, all 16 tumors were confirmed to be truly "HG-SC" by the findings of aberrant p53 staining pattern and/or WT1/p16 positivity, and the lack of mismatch repair deficiency and POLE mutation. In conclusion, HG-SC can on rare occasions show a "squamoid component" mimicking "squamous differentiation." However, the "squamoid component" in HG-SC does not represent true "squamous differentiation." The "squamoid component" is one part of the morphologic spectrum of HG-SC, which should be interpreted carefully for the differential diagnosis of HG-SC and EC. An immunohistochemical panel including p40, p53, p16, and WT1 is a useful adjunct to achieve a correct diagnosis.

E2EFP-MIL: End-to-end and high-generalizability weakly supervised deep convolutional network for lung cancer classification from whole slide image

Efficient and accurate distinction of histopathological subtype of lung cancer is quite critical for the individualized treatment. So far, artificial intelligence techniques have been developed, whose performance yet remained debatable on more heterogenous data, hindering their clinical deployment. Here, we propose an end-to-end, well-generalized and data-efficient weakly supervised deep learning-based method. The method, end-to-end feature pyramid deep multi-instance learning model (E2EFP-MIL), contains an iterative sampling module, a trainable feature pyramid module and a robust feature aggregation module. E2EFP-MIL uses end-to-end learning to extract generalized morphological features automatically and identify discriminative histomorphological patterns. This method is trained with 1007 whole slide images (WSIs) of lung cancer from TCGA, with AUCs of 0.95-0.97 in test sets. We validated E2EFP-MIL in 5 real-world external heterogenous cohorts including nearly 1600 WSIs from both United States and China with AUCs of 0.94-0.97, and found that 100-200 training images are enough to achieve an AUC of >0.9. E2EFP-MIL overperforms multiple state-of-the-art MIL-based methods with high accuracy and low hardware requirements. Excellent and robust results prove generalizability and effectiveness of E2EFP-MIL in clinical practice. Our code is available at https://github.com/raycaohmu/E2EFP-MIL.

Metastatic Lung Cancer to the Head and Neck: A Clinico-Pathological Study on 21 Cases with Narrative Review of the Literature

Metastases from lung cancer to the oral cavity and to the head and neck generally are very infrequent and usually manifest in advanced stages of the disease. Even more rarely, they are the first sign of an unknown metastatic disease. Nevertheless, their occurrence always represents a challenging situation both for clinicians, in the management of very unusual lesions, and for pathologists, in the recognition of the primary site. We retrospectively studied 21 cases of metastases to the head and neck from lung cancer (sixteen males and five females, age range 43-80 years; eight cases localized to the gingiva [two of these to the peri-implant gingiva], seven to the sub-mandibular lymph nodes, two to the mandible, three to the tongue, one case to the parotid gland; in eight patients, metastasis was the first clinical manifestation of an occult lung cancer) and proposed a wide immunohistochemical panel for a proper identification of the primary tumor histotype, including CK5/6, CK8/18, CK7, CK20, p40, p63, TTF-1, CDX2, Chromogranin A, Synaptophysin, GATA-3, Estrogen Receptors, PAX8, PSA. Furthermore, we collected data from previously published studies and narratively reviewed the relevant literature.

Clinicopathological features of cytokeratin 5-positive pulmonary adenocarcinoma

Cytokeratin 5 (CK5) is a marker for pulmonary squamous cell carcinoma; however, CK5 is sometimes present in pulmonary adenocarcinoma (ADC), and there is insufficient information regarding the clinicopathological features of CK5-positive ADC. We aimed to explore the clinicopathological characteristics of CK5-positive ADC using immunohistochemistry. We prepared the following two cohorts: a resected cohort containing 220 resected tumours for primarily studying the detailed morphological characteristics, and a tissue microarray (TMA) cohort containing 337 samples for investigating the associations of CK5 expression with other protein expressions, genetic and prognostic findings. CK5-positive ADC was defined to have ≥ 10% tumour cells and presence of CK5-positive tumour cells in the resected and TMA cohorts, respectively. CK5-positive ADCs were identified in 91 (16.3%) patients in the combined cohort. CK5-positive ADCs had male predominance (P = 0.012), smoking history (P = 0.001), higher stage (P < 0.001), histological high-grade components (P < 0.001), vascular invasion (P < 0.001), mucinous differentiation (P < 0.001), spread through airspaces (P < 0.001), EGFR wild-type (P < 0.001), KRAS mutations (P < 0.001), ALK rearrangement (P < 0.001) and ROS1 rearrangement (P = 0.002). In the resected cohort, more than half the CK5-positive ADCs (19 cases, 65.5%) showed mucinous differentiation; the remaining cases harboured high-grade components. In the TMA cohort, CK5-positive ADCs correlated with TTF-1 negativity (P = 0.002) and MUC5B, MUC5AC and HNF4alpha positivity (P < 0.001, 0.048, < 0.001). Further, CK5-positive ADCs had significantly lower disease-free and overall survival rates than CK5-negative ADCs (P < 0.001 for each). Additionally, multivariate analysis revealed that CK5 expression was an independent poor prognostic factor. CK5-positive ADCs showed aggressive clinical behaviour, with high-grade morphology and mucinous differentiation.

Updates in pathology and molecular diagnostics to inform the evolving landscape of thoracic surgery and oncology

The pathologic assessment of lung cancers provides essential guidance to the surgeon and oncologist who are considering the best treatment strategies for patients with both early and advanced-stage disease. The management of patients with lung cancer is predicated first and foremost on access to an accurate diagnosis, even when the sample size is limited, as is often the case with use of modern, minimally invasive sampling techniques. Once the diagnosis and disease stage are established, predictive biomarker testing may be essential, particularly for those patients with nonsmall cell lung carcinoma (NSCLC) being considered for immunotherapy or genomic biomarker-driven targeted therapy. This review will discuss the best practices for the diagnosis of NSCLC using morphology and immunohistochemistry, thus providing the surgeon with needed information to understand and critically evaluate pathology reports. Controversial and evolving topics including tumor spread through airspaces, evaluation of multiple tumors, and staging based on invasive tumor size will be addressed. Clinical genomic profiling in NSCLC is driven by published guidelines and reflects evidence based on clinical trials and regulatory approvals. In this fast-moving space, surgeons should be aware of the critical immunohistochemical and genomic biomarkers that drive systemic therapy decisions and anticipate when such testing will be required, both to ensure adequate sampling and to advise the pathologist when tumor material will be required for biomarker analysis. The basic approaches to and sample requirements for molecular biomarker testing will be addressed. As biomarker testing moves exclusively from advanced-stage patients into earlier stage disease, the surgeon should be aware of the relevant markers and work with the pathologist and oncologist to ensure that this information is available to facilitate timely access to therapies not just in the advanced setting, but in consideration of neoadjuvant and adjuvant care.

Non-small cell lung carcinomas with diffuse coexpression of TTF1 and p40: clinicopathological and genomic features of 14 rare biphenotypic tumours

Thyroid transcription factor 1 (TTF1) and p40 are widely-utilized diagnostic markers of lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), respectively. Diffuse coexpression of TTF1 and p40 has been described in only rare case reports. In a multi-institutional study, we collected the largest cohort of these unusual tumours to-date (n = 14), with the goal of elucidating their clinicopathological and genomic characteristics. Lung tumours with diffuse coexpression (labelling 50-100% tumour cells) of TTF1 clone 8G7G3/1 and p40 clone BC28 were identified. Detailed clinicopathological and immunohistochemical parameters were analyzed. Eight tumours were analyzed by next-generation sequencing (NGS) and the results were compared to those in > 9 K LUAD and > 1 K LUSC. All tumours with diffuse TTF1/p40 coexpression were poorly differentiated non-small cell lung carcinomas (NSCLC), 42% of which had basaloid features. Some tumours exhibited focal keratinization (14%), napsin A and/or mucicarmine labelling (46%) or both squamous and glandular features (7%). NGS revealed a uniquely high rate of FGFR1 amplifications (70%) compared to either LUAD (0.7%, P < 0.0001) or LUSC (11%, P = 0.001). LUAD-type targetable driver alterations were identified in 38% of cases (one EGFR, two KRAS G12C). The tumours were clinically aggressive, exhibiting metastatic disease in most patients. Lung carcinomas with diffuse TTF1/p40 coexpression represent poorly differentiated NSCLCs with frequent basaloid features, but some show evidence of focal squamous, glandular or dual differentiation with a distinctly high rate of FGFR1 amplifications. The presence of targetable LUAD-type alterations (EGFR, KRAS G12C) emphasizes the importance of molecular testing in these tumours.

A systematic and comprehensive analysis of colorectal squamous cell carcinoma: Implication for diagnosis and treatment

Background

This study was aimed at establishing a nomogram for survival prediction of Colorectal squamous cell carcinoma (CSCC), understanding the molecular pathogenesis, exploring a better treatment, and predicting the potential therapeutic agents.

Methods

Surveillance, Epidemiology, and End Results (SEER) database was used to obtained CSCC patients and the nomogram was performed. Propensity score matching (PSM), Kaplan–Meier analysis, subgroup analysis, and interaction test were used to explore the better treatment strategy for CSCC. Bioinformatics were used to explore the molecular mechanism and potential therapeutic drugs of CSCC.

Results

A total of 3949 CSCC patients were studied. The nomogram was constructed and evaluated to have a good performance. We found that the radiotherapy had a better effect than surgery, and the difference between radiotherapy and combined therapy was not significant. 821 differentially expressed genes in CSCC were obtained from GSE6988 dataset. DNA damage repair, mismatch repair, and cell cycle pathways might contribute to CSCC occurrence as indicated by KEGGpathway and GSEA analysis. Transcription factors analysis revealed that TP63 and STAT1 may have an important role in occurrence and development of CSCC. 1607 potential drugs against CSCC were found using the CMAP database, and molecular docking was carried out to show the binding energy between TP63 and drugs.

Conclusions

A good prognosis nomogram was constructed for CSCC. We also have a better understanding of the underlying molecular mechanisms of occurrence and development of CSCC and predicted potential therapeutic drugs, providing a theoretical basis for the treatment of CSCC.

Case Report: Significant Clinical Benefit From Pemetrexed-Based Therapy in ROS1- and ALK-rearranged Lung Cancer With Adenosquamous Histology

Pemetrexed (used as a platinum doublet or as a maintenance regimen) is an established therapy for patients with advanced non-squamous non-small-cell lung cancer (NSCLC). In addition, certain gene rearrangements (e.g., ALK, ROS1, RET) appear to especially benefit from the use of pemetrexed. Inferior outcomes with pemetrexed compared to other chemotherapies in patients with NSCLC demonstrating squamous histology removed these patients from the labeled indication for the drug. While most squamous cases do not harbor driver oncogenes, rare exceptions exist. Whether the poor outcomes with pemetrexed extend to NSCLC with squamous component harboring driver oncogenes remains unexplored. In this case series, we describe two patients with adenosquamous histology harboring an ROS1 and ALK gene arrangement, respectively, who derived significant benefit from pemetrexed-based therapy. These cases suggest that the value of pemetrexed may need to be re-explored in adenosquamous NSCLC harboring such alterations.

Development and Validation of a Concise Prediction Scoring System for Asian Lung Cancer Patients with EGFR Mutation Before Treatment

Purpose We aimed to determine the epidermal growth factor receptor (EGFR) genetic profile of lung cancer in Asians, and develop and validate a non-invasive prediction scoring system for EGFR mutation before treatment. Methods This was a single-center retrospective cohort study using data of patients with lung cancer who underwent EGFR detection (n = 1450) from December 2014 to October 2020. Independent predictors were filtered using univariate and multivariate logistic regression analyses. According to the weight of each factor, a prediction scoring system for EGFR mutation was constructed. The model was internally validated using bootstrapping techniques and temporally validated using prospectively collected data (n = 210) between November 2020 and June 2021.Results In 1450 patients with lung cancer, 723 single mutations and 51 compound mutations were observed in EGFR. Thirty-nine cases had two or more synchronous gene mutations. We developed a scoring system according to the independent clinical predictors and stratified patients into risk groups according to their scores: low-risk (score <4), moderate-risk (score 4-8), and high-risk (score >8) groups. The C-statistics of the scoring system model was 0.754 (95% CI 0.729-0.778). The factors in the validation group were introduced into the prediction model to test the predictive power of the model. The results showed that the C-statistics was 0.710 (95% CI 0.638-0.782). The Hosmer–Lemeshow goodness-of-fit showed that χ² = 6.733, P = 0.566. Conclusions The scoring system constructed in our study may be a non-invasive tool to initially predict the EGFR mutation status for those who are not available for gene detection in clinical practice.

The extent of expression of thyroid transcription factor 1, cytokeratin 7, and anaplastic lymphoma kinase in lung adenocarcinoma

Background:

New forms of genetic alteration were developed giving a new era of lung adenocarcinoma (AdC) with diverse clinical and pathological features.

Aim and Objectives:

The aim is to investigate the ALK-rearranged gene as one of these genetic alterations in AdC. The role of TTF-1 and CK7 is to exclude the metastases.

Material and Methods:

Paraffin-embedded 50 AdC specimens were cut into 4-mm thick sections and stained with the primary antibody, using an anti-TTF-1 antibody, (all at a 1:200 dilution, mouse monoclonal antibody; Dako, Denmark), anti-CK 7 antibody (DAKO, Carpentaria, CA), and the rabbit monoclonal anti- ALK antibody (D5F3) (Ventana, USA). Positive reactivity was considered as brown nuclear immunostaining for TTF-1 and cytoplasmic for CK 7and both cytoplasmic and nuclear for ALK.

Results:

The median age was 56±2, with male to female ratio 7:3. Forty-four cases revealed a mixed pattern (88%), with focal intraluminal mucin. Forty-one cases (82%) were positive for TTF-1, of these; weak (13; %), moderate (16; %) and strong (12; %). Regarding CK7; 48 cases (96%) were positive; weak (7 cases; 14.5; %), moderate (18 cases; 37.5%) and strong (23 case; 47.9 %) of the positive cases. Regarding D5F3; five cases (10%) were positive; weak (1 case; 20 %), moderate (2 cases; 40 %) and strong (2 cases; 40%) out of the positive cases. Four ALK-positive cases were male and ALK-positive patients ranged from 42-55 years with median 48.

Conclusion:

Despite the incidence of ALk-AdC is uncommon, it might be suspected in lesions of lower age group especially with mucinous foci.

Coexpression of ΔNp63/p40 and TTF1 Within Most of the Same Individual Cells Identifies Life-Threatening NSCLC Featuring Squamous and Glandular Biphenotypic Differentiation: Clinicopathologic Correlations

Introduction

Double occurrence of TTF1 and ΔNp63/p40 (henceforth, p40) within the same individual cells is exceedingly rare in lung cancer. Little is known on their biological and clinical implications.

Methods

Two index cases immunoreactive for both p40 and TTF1 and nine tumors selected from The Cancer Genome Atlas (TCGA) according to the mRNA levels of the two relevant genes entered the study.

Results

The two index cases were peripherally located, poorly differentiated, and behaviorally unfavorable carcinomas, which shared widespread p40 and TTF1 decoration within the same individual tumor cells. They also retained SMARCA2 and SMARCA4 expression, while variably stained for p53, cytokeratin 5, and programmed death-ligand 1. A subset of basal cells p40+/TTF1+ could be found in normal distal airways. Biphenotypic glandular and squamous differentiation was unveiled by electron microscopy, along with EGFR, RAD51B, CCND3, or NF1 mutations and IGF1R, MYC, CCND1, or CDK2 copy number variations on next-generation sequencing analysis. The nine tumors from TCGA (0.88% of 1018 tumors) shared the same poor prognosis, clinical presentation, and challenging histology and had activated pathways of enhanced angiogenesis and epithelial-mesenchymal transition. Mutation and copy number variation profiles did not differ from the other TCGA tumors.

Conclusions

Double p40+/TTF1+ lung carcinomas are aggressive and likely underrecognized non-small cell carcinomas, whose origin could reside in double-positive distal airway stem-like basal cells through either de novo-basal-like or differentiating cell mechanisms according to a model of epithelial renewal.

Recommendations for immunocytochemistry in lung cancer typing: An update on a resource-efficient approach with large-scale comparative Bayesian analysis

OBJECTIVES

The majority of lung cancer cases are of advanced stage and diagnosis is usually made using minimally invasive small biopsies and cytological specimens. The WHO 2015 classification recommends limiting immunocytochemistry (ICC) to lung cancer typing and molecular testing drives for personalised therapies. An algorithm using Bayes' theorem could be useful for defining antibody profiles. This study aims to assess the impact of different antibody profiles for cytological samples on the accuracy of lung cancer typing with a large-scale Bayesian analysis.

METHODS

A retrospective examination of 3419 consecutive smears and/or cytospins diagnosed over 2011-2016 found 1960 primary lung cancer tumours: 972 adenocarcinomas (ADC), 256 squamous carcinomas (SQC), 268 neuroendocrine tumours (NET), and 464 non-small cell cancer-not otherwise specified (NSCC-NOS). The a priori and a posteriori probabilities, before and after ICC using antibodies singly or in combination, were calculated for different lung cancer types.

RESULTS

TTF-1 or CK7 alone improved the a posteriori probabilities of correct cytological typing for ADC to 86.5% and 95.8%, respectively. For SQC, using p40 (∆Np63) or CK5/6 together with CK5/14 led to comparable results (78.3% and 90.3%). With synaptophysin or CD56 alone, improvements in a posteriori probabilities to 87.5 and 90.3% for the correct recognition of NET could be achieved.

CONCLUSIONS

Based on morphological and clinical data, the use of two antibodies appears sufficient for reliable detection of the different lung cancer types. This applies to diagnoses that were finalised following ICC both on a clinical or cytological basis and on a histological basis.

Molecular cytology of the respiratory tract and pleura

There is growing evidence that molecular testing is feasible on all types of cytological preparation, which is fortunate as more diagnostic markers and biomarkers for targeted therapies are discovered for use in pulmonary and pleural malignancies. In this article we will discuss the pre-analytic, analytic, and post-analytic (interpretive) considerations for successful implementation of molecular tests for diagnostic and predictive markers in respiratory and pleural cytology. The vast majority of laboratories are familiar with, and have validated their molecular protocols for, formalin-fixed paraffin-embedded surgical specimens, which are not directly applicable to cytology specimens. Thus, rigorous validation must be performed for each type of fixative and cytology preparation before it is implemented in the clinical setting.

Epithelial cell plasticity: breaking boundaries and changing landscapes

Epithelial tissues respond to a wide variety of environmental and genotoxic stresses. As an adaptive mechanism, cells can deviate from their natural paths to acquire new identities, both within and across lineages. Under extreme conditions, epithelial tissues can utilize "shape-shifting" mechanisms whereby they alter their form and function at a tissue-wide scale. Mounting evidence suggests that in order to acquire these alternate tissue identities, cells follow a core set of "tissue logic" principles based on developmental paradigms. Here, we review the terminology and the concepts that have been put forward to describe cell plasticity. We also provide insights into various cell intrinsic and extrinsic factors, including genetic mutations, inflammation, microbiota, and therapeutic agents that contribute to cell plasticity. Additionally, we discuss recent studies that have sought to decode the "syntax" of plasticity-i.e., the cellular and molecular principles through which cells acquire new identities in both homeostatic and malignant epithelial tissues-and how these processes can be manipulated for developing novel cancer therapeutics.

Radiomics-Based Features for Prediction of Histological Subtypes in Central Lung Cancer

Objectives

To evaluate the effectiveness of radiomic features on classifying histological subtypes of central lung cancer in contrast-enhanced CT (CECT) images.

Materials and Methods

A total of 200 patients with radiologically defined central lung cancer were recruited. All patients underwent dual-phase chest CECT, and the histological subtypes (adenocarcinoma (ADC), squamous cell carcinoma (SCC), small cell lung cancer (SCLC)) were confirmed by histopathological samples. 107 features were used in five machine learning classifiers to perform the predictive analysis among three subtypes. Models were trained and validated in two conditions: using radiomic features alone, and combining clinical features with radiomic features. The performance of the classification models was evaluated by the area under the receiver operating characteristic curve (AUC).

Results

The highest AUCs in classifying ADC vs. SCC, ADC vs. SCLC, and SCC vs. SCLC were 0.879, 0.836, 0.783, respectively by using only radiomic features in a feedforward neural network.

Conclusion

Our study indicates that radiomic features based on the CECT images might be a promising tool for noninvasive prediction of histological subtypes in central lung cancer and the neural network classifier might be well-suited to this task.

Difficulties in diagnostics of lung tumours in biopsies: an interpathologist concordance study evaluating the international diagnostic guidelines

AIMS

Accurate and reliable diagnosis is essential for lung cancer treatment. The study aim was to investigate interpathologist diagnostic concordance for pulmonary tumours according to WHO diagnostic criteria.

METHODS

Fifty-two unselected lung and bronchial biopsies were diagnosed by a thoracic pathologist based on a broad spectrum of immunohistochemical (IHC) stainings, molecular data and clinical/radiological information. Slides stained with H&E, thyroid transcription factor-1 (TTF-1) clone SPT24 and p40 were scanned and provided digitally to 20 pathologists unaware of reference diagnoses. The pathologists independently diagnosed the cases and stated if further diagnostic markers were deemed necessary.

RESULTS

In 31 (60%) of the cases, ≥80% of the pathologists agreed with each other and with the reference diagnosis. Lower agreement was seen in non-small cell neuroendocrine tumours and in squamous cell carcinoma with diffuse TTF-1 positivity. Agreement with the reference diagnosis ranged from 26 to 45 (50%-87%) for the individual pathologists. The pathologists requested additional IHC staining in 15-44 (29%-85%) of the 52 cases. In nearly half (17 of 36) of the malignant cases, one or more pathologist advocated for a different final diagnosis than the reference without need of additional IHC markers, potentially leading to different clinical treatment.

CONCLUSIONS

Interpathologist diagnostic agreement is moderate for small unselected bronchial and lung biopsies based on a minimal panel of markers. Neuroendocrine morphology is sometimes missed and TTF-1 clone SPT24 should be interpreted with caution. Our results suggest an intensified education need for thoracic pathologists and a more generous use of diagnostic IHC markers.

Glypican-1 is a novel immunohistochemical marker to differentiate poorly differentiated squamous cell carcinoma from solid predominant adenocarcinoma of the lung

Background

The histological classification of non-small cell lung cancer (NSCLC) is essential in determining new cancer-specific targeted therapies. However, the accurate typing of poorly differentiated is difficult, particularly for poorly differentiated squamous cell carcinoma and adenocarcinoma of the lung with limited immunohistochemical markers. Thus, novel immunohistochemical markers are required. We assumed the possibility of the immunohistochemical expression of glypican-1 in lung squamous cell carcinoma.

Methods

The microarray dataset GSE43580 from Gene Expression Omnibus database were analyzed for confirming the gene expression of glypican-1 in lung squamous cell carcinoma. We immunohistochemically investigated the use of glypican-1 as a novel positive diagnostic marker for lung squamous cell carcinoma. Glypican-1 expression in 63 cases of poorly differentiated lung squamous cell carcinoma and 60 cases of solid predominant lung adenocarcinoma was investigated by immunohistochemistry. Additionally, we compared glypican-1 expression with the expressions of p40, cytokeratin 5/6, thyroid transcription factor-1 (TTF-1), and napsin A.

Results

All 63 cases of lung squamous cell carcinoma showed glypican-1 expression. In contrast, only 2 cases of lung adenocarcinoma showed glypican-1 expression. The sensitivity, specificity, and diagnostic accuracy of glypican-1 expression for differentiating lung squamous cell carcinoma from lung adenocarcinoma were 100%, 96.7%, and 98.4%, respectively. These were similar to those of p40 and significantly better than those of CK 5/6.

Conclusions

We recommend the use of glypican-1 as an additional positive marker of lung squamous cell carcinoma.

Creation of Formalin-Fixed, Paraffin-Embedded 3D Lung Cancer Cellular Spheroids for the Optimization of Immunohistochemistry Staining Procedures

In an era of precision medicine important treatment decisions are dictated by expression of clinically informative tumor protein biomarkers. These biomarkers can be detected by immunohistochemistry (IHC) performed in tumor tissue sections obtained from biopsies or resections. Like all experimental procedures, IHC needs optimization for several of its steps. However, the investigator must avoid optimizing the IHC procedure using valuable human biopsy samples which may be difficult to obtain. Ideally, valuable biopsy samples should only be subjected to IHC once the IHC protocol has been optimized. In this chapter, we describe a procedure for IHC optimization using tri-dimensional (3D) cellular spheroids created from cultured cells. In this approach, cultured cells are pelleted into 3D spheroids, which are then processed just like a tissue sample, namely, fixed, embedded, sectioned, mounted on slides, and stained with IHC just like a human tissue sample. These 3D cellular spheroids have a tissue-like architecture and cellularity resembling a tumor section, and both cellular and antigen structure are preserved. This method is therefore acceptable for IHC optimization before proceeding to the IHC staining of human tumor samples.

Clinicopathological Features of Thyroid-Like Low-Grade Nasopharyngeal Papillary Adenocarcinoma: A Case Report and Review of the Literature

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare neoplasm of the nasopharynx. Accordingly, its clinical and pathological characteristics are not well-known. We report a case of TL-LGNPPA and review the relevant literature on TL-LGNPPA. A 38-year-old Japanese woman presented with a history of nasal obstruction that had persisted for 1 month after symptoms of a common cold (e.g., low-grade fever, sore throat, and fatigue). A pedunculated tumor of ~20 mm in diameter was found on the posterior edge of the nasal septum. The tumor was endoscopically resected. Based on careful histopathological and immunohistochemical examinations, it was diagnosed as TL-LGNPPA. At 5 years after surgery, the patient remained disease-free. TL-LGNPPA has a very good prognosis, and complete resection with a sufficient safety margin is recommended as the first-line treatment. The morphological characteristics and immunohistochemical findings, especially TTF-1 positivity and thyroglobulin negativity, are important for the diagnosis.

Diagnostic patterns of non-small-cell lung cancer at Princess Margaret Cancer Centre

Background

Accurate classification of lung cancer subtypes has become critical in tailoring lung cancer treatment. Our study aimed to evaluate changes in diagnostic testing and pathologic subtyping of advanced non-small-cell lung cancer (nsclc) over time at a major cancer centre.

Methods

In a review of patients diagnosed with advanced nsclc at Princess Margaret Cancer Centre between 2007-2009 and 2013-2015, diagnostic method, sample type and site, pathologic subtype, and use of immunohistochemistry (ihc) staining and molecular testing were abstracted.

Results

The review identified 238 patients in 2007-2009 and 283 patients in 2013-2015. Over time, the proportion of patients diagnosed with adenocarcinoma increased to 73.1% from 60.9%, and diagnoses of nsclc not otherwise specified (nos) decreased to 6.4% from 18.9%, p < 0.0001. Use of diagnostic bronchoscopy decreased (26.9% vs. 18.4%), and mediastinal sampling procedures, including endobronchial ultrasonography, increased (9.2% vs. 20.5%, p = 0.0001). Use of ihc increased over time to 76.3% from 41.6% (p < 0.0001). Larger surgical or core biopsy samples and those for which ihc was performed were more likely to undergo biomarker testing (both p < 0.01).

Conclusions

Customizing treatment based on pathologic subtype and molecular genotype has become key in treating patients with advanced lung cancer. Greater accuracy of pathology diagnosis is being achieved, including through the routine use of ihc.

Patient-derived cell line, xenograft and organoid models in lung cancer therapy

Lung cancer accounts for most cancer-related deaths worldwide and has an overall 5-year survival rate of ~15%. Cell lines have played important roles in the study of cancer biology and potential therapeutic targets, as well as pre-clinical testing of novel drugs. However, most experimental therapies that have cleared preclinical testing using established cell lines have failed phase III clinical trials. This suggests that such models may not adequately recapitulate patient tumor biology and clinical outcome predictions. Here, we discuss and compare different pre-clinical lung cancer models, including established cell lines, patient-derived cell lines, xenografts and organoids, summarize the methodology for generating these models, and review their relative advantages and limitations in different oncologic research applications. We further discuss additional gaps in patient-derived pre-clinical models to better recapitulate tumor biology and improve their clinical predictive power.

Appreciation of Pattern in Diagnosis of Lung Adenocarcinoma from Cytology Specimen: Our Experience with Fine Needle Aspiration Cytology and Cell Block in a Resource Constraint Setup

BACKGROUND AND AIMS

Advent of personalised treatment needs correct diagnosis of lung adenocarcinoma with its molecular subtyping. Minimal use of special stain or immunohistochemistry (IHC) in small specimens save material for molecular testing. Various histologic patterns in adenocarcinoma (ADC) subtypes have different prognostic implications and current recommendation is to describe these patterns in small specimens. Aim of this study was to diagnose adenocarcinoma from cytology specimens depending on adenocarcinoma pattern on fine needle aspiration smears and cell blocks. We also studied the additional role of cell blocks as a platform for special stain and IHC.

MATERIALS AND METHODS

Conventional smears and cell block (CB) preparation were examined from transthoracic CT guided FNA samples of suspicious lung malignancy cases. Clear defining architectural pattern and cytomorphological features in favour of adenocarcinoma were evaluated and mucin stain and IHC were used as and when required.

RESULTS

A total of 86 cases were included in this study, of which 83 cases were diagnosed as adenocarcinoma, 52 (62.5%) showed clear cut evidence of adenocarcinoma from smears and CBs. CB morphology alone aided the diagnosis in 12. Various ADC patterns in combination or alone were appreciated in these 64 cases. Sixteen needed mucin stain and 3 needed IHC for diagnosis. Forty one were ADC with solid pattern of which 39 showed high nuclear grade.

CONCLUSION

Adequately cellular FNA smears and corresponding cell blocks of optimal quality can aid effectively in diagnosing adenocarcinoma and appreciating its pattern. Therefore, it would minimize the need for special stain and/or IHC with preservation of more material for molecular testing.

ATR-FTIR spectroscopy as adjunct method to the microscopic examination of hematoxylin and eosin-stained tissues in diagnosing lung cancer

Lung cancer remains the leading cause of cancer-related death worldwide. Since prognosis and treatment outcomes rely on fast and accurate diagnosis, there is a need for more cost-effective, sensitive, and specific method for lung cancer detection. Thus, this study aimed to determine the ability of ATR-FTIR in discriminating malignant from benign lung tissues and evaluate its concordance with H&E staining. Three (3) 5μm-thick sections were cut from formalin fixed paraffin embedded (FFPE) cell or tissue blocks from patients with lung lesions. The outer sections were H&E-stained and sent to two (2) pathologists to confirm the histopathologic diagnosis. The inner section was deparaffinized by standard xylene method and then subjected to ATR-FTIR analysis. Distinct spectral profiles that distinguished (p<0.05) one sample from another, called the "fingerprint region", were observed in five (5) peak patterns representing the amides, lipids, and nucleic acids. Principal component analysis and hierarchical cluster analysis evidently clustered the benign from malignant tissues. ATR-FTIR showed 97.73% sensitivity, 92.45% specificity, 94.85% accuracy, 91.49% positive predictive value and 98.00% negative predictive value in discriminating benign from malignant lung tissue. Further, strong agreement was observed between histopathologic readings and ATR-FTIR analysis. This study shows the potential of ATR-FTIR spectroscopy as a potential adjunct method to the gold standard, the microscopic examination of hematoxylin and eosin (H&E)-stained tissues, in diagnosing lung cancer.

Head-to-Head Comparison of p63 and p40 in Non-Neuroendocrine Carcinomas of the Tubal Gut

OBJECTIVES.

With targeted agents, characterizing carcinomas of the gastrointestinal (GI) tract has become more important. We aim to determine the usefulness of p40 in classifying GI tract carcinomas.

METHODS.

Seventy-five GI carcinomas including 28 squamous cell carcinomas (SCC), 2 adenosquamous carcinomas (ASCA), 21 poorly differentiated carcinomas (PDCA), and 24 adenocarcinomas (AdCA; control group) were stained for p40, p63, and CK5/6. Tumors were scored from 0 to 5 based on extent of staining and marked as positive (score >2) or negative.

RESULTS.

p63 was positive in 100% of SCC/ASCA and 12.5% of AdCA. p40 was positive in 92.5% of SCC/ASCA and 4.1% of AdCA. In the PDCA subset, a panel including p63, p40, and MOC31 was the best way to accurately classify most cases.

CONCLUSIONS.

p63 and CK5/6 are more sensitive but less specific than p40 for SCC/ASCA in GI carcinomas. In PDCA, a panel approach including p63, CK5/6, and p40 may be best in classifying these cases.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

The prognostic effect of TTF-1 expression in the Chinese population of patients with advanced lung adenocarcinomas

Background

Thyroid transcription factor 1 (TTF-1), which is usually expressed by lung adenocarcinomas and small cell carcinomas, is usually used to distinguish adenocarcinoma and small cell carcinoma from cells of another type of lung cancer. We examined the association between TTF-1 expression and overall survival between patients with stage IV pulmonary adenocarcinoma to investigate the role of TTF-1 as a predictive and/or prognostic tumor marker in patients with advanced lung adenocarcinomas.

Methods

Analysis of the clinicopathologic features, treatment regimens, and overall survival of 209 lung adenocarcinoma patients who had been detected for TTF-1 expression and received consecutive treatments in the Affiliated Hospital of Qingdao University.

Results

TTF-1 expression was positive in 166 (79%) and negative in 43 (21%) patients who were reviewed. Moreover, there was no significant difference between the clinicopathologic features of TTF-1 positive and TTF-1 negative tumors. In the multivariable review, the overall survival of TTF-1 positive tumor patients was significantly longer than that of TTF-1 negative tumor patients [22.7 vs. 11.8 months (P<0.0001)], increasing the prognostic effect of Karnofsky performance status and receiving first-line chemotherapy or targeted therapy. Positive TTF-1 and negative TTF-1 patients receiving pemetrexed-based chemotherapy improved the duration of treatment compared to those receiving non-pemetrexed chemotherapy.

Conclusions

TTF-1 expression was associated with an improved survival in patients with advanced lung adenocarcinomas. Both patients, either TTF-1 positive or negative, could benefit from the first-line chemotherapy or pemetrexed treatment option. However, as discovered by our investigation, TTF-1 cannot forecast a portion of the lung adenocarcinomas that had a selective sensitivity to pemetrexed.

Specific Deletion of p16INK4a with Retention of p19ARF Enhances the Development of Invasive Oral Squamous Cell Carcinoma

The cyclin-dependent kinase inhibitor 2A (CDKN2A)/alternate reading frame (ARF) locus consists of two overlapping tumor suppressor genes, p16^INK4a and p14^ARF (p19^ARF in mice), encoding two unrelated proteins in alternative reading frames. Previous reports suggest that p16^INK4a and p14^ARF alterations independently exhibit differential roles, and p16^INK4a is more closely associated with a poor prognosis in oral cancer. However, the role of p16^INK4a-specific loss in oral squamous cell carcinogenesis remains unclear. The authors assessed chemical carcinogen 4-nitroquinoline 1-oxide (4NQO)-induced multistep oral squamous cell carcinogenesis in mice carrying p16^INK4a-specific loss with retention of the p19^ARF gene (p16^INK4a-/-). 4NQO-treated p16^-/- mice exhibited a higher incidence and multiplicity of oral squamous cell carcinoma (OSCC) development relative to 4NQO-treated wild-type mice. 4NQO-treated p16^INK4a-/- OSCC cells exhibited higher proliferation and up-regulation of Arf, transcription factor E2f1, tumor protein p63 (tp63), and oncogenic ΔNp63, an isoform p63, compared with observations in 4NQO-treated wild-type OSCC cells. Furthermore, the overexpression of oncogenic ΔNp63 was associated with human OSCC. In conclusion, these results in mice indicate the biological significance of p16^INK4a-specific loss with retention of p19^ARF in oral squamous cell carcinogenesis, and ΔNp63 may be a potential target for OSCC.

The value of desmosomal plaque-related markers to distinguish squamous cell carcinoma and adenocarcinoma of the lung

Background: An antibody panel is needed to definitively differentiate between adenocarcinoma (AC) and squamous cell carcinoma (SCC) in order to meet more stringent requirements for the histologic classification of lung cancers. Staining of desmosomal plaque-related proteins may be useful in the diagnosis of lung SCC.Materials and methods: We compared the usefulness of six conventional (CK5/6, p40, p63, CK7, TTF1, and Napsin A) and three novel (PKP1, KRT15, and DSG3) markers to distinguish between lung SCC and AC in 85 small biopsy specimens (41 ACs and 44 SCCs). Correlations were examined between expression of the markers and patients' histologic and clinical data.Results: The specificity for SCC of membrane staining for PKP1, KRT15, and DSG3 was 97.4%, 94.6%, and 100%, respectively, and it was 100% when the markers were used together and in combination with the conventional markers (AUCs of 0.7619 for Panel 1 SCC, 0.7375 for Panel 2 SCC, 0.8552 for Panel 1 AC, and 0.8088 for Panel 2 AC). In a stepwise multivariate logistic regression model, the combination of CK5/6, p63, and PKP1 in membrane was the optimal panel to differentiate between SCC and AC, with a percentage correct classification of 96.2% overall (94.6% of ACs and 97.6% of SCCs). PKP1 and DSG3 are related to the prognosis.Conclusions: PKP1, KRT15, and DSG3 are highly specific for SCC, but they were more useful to differentiate between SCC and AC when used together and in combination with conventional markers. PKP1 and DSG3 expressions may have prognostic value.

Successful lung cancer EGFR sequencing from DNA extracted from TTF-1 immunohistochemistry slides: a new means to extend insufficient tissue

Lung cancer biopsy material is limited and is used for morphologic diagnosis and immunohistochemical and molecular testing. This can lead to tissue exhaustion, resulting in repeat biopsies (when clinically possible), delayed testing, and increased risks. Consequently, there is a need to optimize preanalytical specimen use for molecular testing. Although hematoxylin/eosin can be used for as a DNA source for molecular testing, little is known regarding the potential use of immunohistochemistry (IHC) slides, as these are subject to harsh conditions that can lead to DNA degradation. Our aim was to evaluate whether DNA extracted from TTF-1 IHC slides, a common stain for lung adenocarcinoma, can be tested for EGFR mutations. Twenty-two lung adenocarcinoma samples (11 EGFR wild type and 11 mutated) were selected. Slides were stained for TTF-1 IHC. Following TTF-1 staining, tissue underwent DNA extraction. Pyrosequencing for mutations in exons 18, 19, 20, and 21 of EGFR was performed, and results were compared to clinical EGFR testing data. All 22 TTF-1 samples produced successful results, and 21 were concordant. Of the 11 originally EGFR-mutated cases, 10 TTF-1 samples showed identical mutations in all exons of interest. One case with an L858R mutation on original testing was negative on sequencing of the TTF-1 sample, possibly due to lower tumor burden on the TTF-1 stained slide. All 11 originally EGFR wild-type cases showed identical results on the TTF-1 samples. TTF-1 IHC slides can be a viable DNA source for molecular testing, especially important in lung biopsies with insufficient material following diagnostic evaluation.

TTF-1/p63-Positive Poorly Differentiated NSCLC: A Histogenetic Hypothesis from the Basal Reserve Cell of the Terminal Respiratory Unit

TTF-1 is expressed in the alveolar epithelium and in the basal cells of distal terminal bronchioles. It is considered the most sensitive and specific marker to define the adenocarcinoma arising from the terminal respiratory unit (TRU). TTF-1, CK7, CK5/6, p63 and p40 are useful for typifying the majority of non-small-cell lung cancers, with TTF and CK7 being typically expressed in adenocarcinomas and the latter three being expressed in squamous cell carcinoma. As tumors with coexpression of both TTF-1 and p63 in the same cells are rare, we describe different cases that coexpress them, suggesting a histogenetic hypothesis of their origin. We report 10 cases of poorly differentiated non-small-cell lung carcinoma (PD-NSCLC). Immunohistochemistry was performed by using TTF-1, p63, p40 (ΔNp63), CK5/6 and CK7. EGFR and BRAF gene mutational analysis was performed by using real-time PCR. All the cases showed coexpression of p63 and TTF-1. Six of them showing CK7+ and CK5/6− immunostaining were diagnosed as “TTF-1+ p63+ adenocarcinoma”. The other cases of PD-NSCLC, despite the positivity for CK5/6, were diagnosed as “adenocarcinoma, solid variant”, in keeping with the presence of TTF-1 expression and p40 negativity. A “wild type” genotype of EGFR was evidenced in all cases. TTF1 stained positively the alveolar epithelium and the basal reserve cells of TRU, with the latter also being positive for p63. The coexpression of p63 and TTF-1 could suggest the origin from the basal reserve cells of TRU and represent the capability to differentiate towards different histogenetic lines. More aggressive clinical and morphological features could characterize these “basal-type tumors” like those in the better known “basal-like” cancer of the breast.

Complementary value of electron microscopy and immunohistochemistry in the diagnosis of non-small cell lung cancer: A potential role for electron microscopy in the era of targeted therapy

With the identification of therapeutic targets for lung adenocarcinoma, it has become mandatory to distinguish it from other entities. Some cases remain classified as non-small cell lung carcinoma, not otherwise specified (NSCLC-NOS) with immunohistochemistry. Electron microscopy (EM) can be useful, allowing the identification of glandular differentiation. The aim of this study was to determine the complementary value of immunohistochemistry and EM.Forty-eight NSCLC-NOS cases were selected (PSMAR-Biobank, Barcelona, Spain). Immunohistochemistry (TTF-1, p40) was performed. Tissue was retrieved from paraffin blocks. Results were compared to the final diagnosis, derived from combination of light microscopy, immunohistochemistry, EM, molecular studies and resection specimen.Immunohistochemistry concurred with final diagnosis in 36 cases (75%, Kappa = 0.517). EM agreed with final diagnosis in 35 (72.9%, Kappa = 0.471). Immunohistochemistry had a sensitivity = 73%, specificity = 100%, positive predictive value (PPV) = 100% and negative predictive value (NPV) = 52.4% for adenocarcinoma. All adenocarcinoma cases not solved by immunohistochemistry (n = 10) were classified by EM, and vice versa. Data from EM were identical to those of immunohistochemistry: sensitivity = 73%, specificity = 100%, PPV = 100% and NPV = 52.4%. Combining both techniques, 47 cases were coincident with final diagnosis (97.9%, Kappa = 0.943).EM can provide valuable information in subtyping NSCLC-NOS, being particularly useful when immunohistochemistry is inconclusive. EM could be considered as a complementary tool for decision-making in NSCLC-NOS.

Mechanisms of resistance to pemetrexed in non-small cell lung cancer

Currently, lung cancer has remained the most common cause of cancer death while non-small cell lung cancer (NSCLC) accounts for the most of all lung cancer cases. Regardless of multiple existing managements, chemotherapy regimens are still the mainstay of treatment for NSCLC, where pemetrexed has shown cytotoxic activity and has increasingly been used, especially for advanced cases. However, chemo-resistance may inhibit clinical efficacy after long-term use. Mechanisms responsible for chemo-resistance to pemetrexed in NSCLC are plethoric but can be separated into two categories to be discussed: tumor cells and their interactions with drugs. Phenomena relevant to tumor cells such as oncogene or oncoprotein alterations, DNA synthesis, DNA repair, and tumor cell biology behavior are discussed, as well as processes associated with drug dynamics, including drug uptake, drug elimination, and antifolate polyglutamylation. This review will focus on clinical trials and the basic biomedical mechanisms of NSCLC treated with pemetrexed and will describe the underlying mechanisms of resistance to facilitate more efficient clinical therapies to treat patients.

Clinical And Imageological Features Of Lung Squamous Cell Carcinoma With EGFR Mutations

Purpose

To analyze the distribution of epidermal growth factor receptor (EGFR) mutations; characterize the clinical and imageological features of lung squamous cell carcinoma (LSCC) in a large population of patients; and assess correlations between clinical and imageological characteristics and clinical outcomes of LSCC patients harboring EGFR mutations.

Patients and methods

Three pathologists retrospectively evaluated the morphological and immunohistochemical data of 2,322 patients with LSCC resected between February 2013 and December 2017. Data on the distribution of EGFR mutations and the clinical and imageological characteristics of the patients were retrospectively collected. Correlations between the EGFR mutation status and clinical outcomes were evaluated using univariate and multivariate analyses.

Results

EGFR mutations were found in 3.4% of patients with LSCC and predominantly in female and non-smoking patients. Tumor lesions in patients with EGFR-positive mutations were more irregularly shaped than those in patients with EGFR-negative mutations (P = 0.045). In non-smoking patients with LSCC, the proportion of marked spiculation was significantly higher in the EGFR-positive group than in the EGFR-negative group (P = 0.043). No significant difference in recurrence-free survival was noted between LSCC patients harboring EGFR-positive and those harboring EGFR-negative mutations. No difference in metastases was observed between the EGFR-positive and EGFR-negative cohorts.

Conclusion

Female gender, non-smoking habit, irregularly shaped tumor, and marked spiculation might predict the presence of EGFR mutations in LSCC. The administration of tyrosine kinase inhibitors to patients with LSCC after screening for EGFR mutations based on their clinical and imageological features would likely result in a population with a greater sensitivity to afatinib.