The histologic phenotype of lung cancers is associated with transcriptomic features rather than genomic characteristics

Histology plays an essential role in therapeutic decision-making for lung cancer patients. However, the molecular determinants of lung cancer histology are largely unknown. We conduct whole-exome sequencing and microarray profiling on 19 micro-dissected tumor regions of different histologic subtypes from 9 patients with lung cancers of mixed histology. A median of 68.9% of point mutations and 83% of copy number aberrations are shared between different histologic components within the same tumors. Furthermore, different histologic components within the tumors demonstrate similar subclonal architecture. On the other hand, transcriptomic profiling reveals shared pathways between the same histologic subtypes from different patients, which is supported by the analyses of the transcriptomic data from 141 cell lines and 343 lung cancers of different histologic subtypes. These data derived from mixed histologic subtypes in the setting of identical genetic background and exposure history support that the histologic fate of lung cancer cells is associated with transcriptomic features rather than the genomic profiles in most tumors.

Comprehensive molecular characterization of lung tumors implicates AKT and MYC signaling in adenocarcinoma to squamous cell transdifferentiation

Background Lineage plasticity, the ability to transdifferentiate among distinct phenotypic identities, facilitates therapeutic resistance in cancer. In lung adenocarcinomas (LUADs), this phenomenon includes small cell and squamous cell (LUSC) histologic transformation in the context of acquired resistance to targeted inhibition of driver mutations. LUAD-to-LUSC transdifferentiation, occurring in up to 9% of EGFR-mutant patients relapsed on osimertinib, is associated with notably poor prognosis. We hypothesized that multi-parameter profiling of the components of mixed histology (LUAD/LUSC) tumors could provide insight into factors licensing lineage plasticity between these histologies. Methods We performed genomic, epigenomics, transcriptomics and protein analyses of microdissected LUAD and LUSC components from mixed histology tumors, pre-/post-transformation tumors and reference non-transformed LUAD and LUSC samples. We validated our findings through genetic manipulation of preclinical models in vitro and in vivo and performed patient-derived xenograft (PDX) treatments to validate potential therapeutic targets in a LUAD PDX model acquiring LUSC features after osimertinib treatment. Results Our data suggest that LUSC transdifferentiation is primarily driven by transcriptional reprogramming rather than mutational events. We observed consistent relative upregulation of PI3K/AKT, MYC and PRC2 pathway genes. Concurrent activation of PI3K/AKT and MYC induced squamous features in EGFR-mutant LUAD preclinical models. Pharmacologic inhibition of EZH1/2 in combination with osimertinib prevented relapse with squamous-features in an EGFR-mutant patient-derived xenograft model, and inhibition of EZH1/2 or PI3K/AKT signaling re-sensitized resistant squamous-like tumors to osimertinib. Conclusions Our findings provide the first comprehensive molecular characterization of LUSC transdifferentiation, suggesting putative drivers and potential therapeutic targets to constrain or prevent lineage plasticity.

Histopathologic spectrum of glomangioma: A clinico-pathologic review

Introduction/Objective Glomus tumors are mesenchymal neoplasms with glomus body type modified smooth muscle cell differentiation. Most glomus tumors have a benign clinical course. However, rarely, they display malignant histologic features. Methods/Case Report We undertook a retrospective study using a natural language search in CoPath to find surgical pathology cases from 1993-2020 containing “glomus” in the pathology diagnosis. All relevant cases were included, and clinicopathologic data were reviewed in detail. Results (if a Case Study enter NA) A total of 66 tumors were identified, of which 42 were in female (63.6%) and 24 in male (36.4%) patients. The age at surgery ranged from 22 to 79 years with a median of 47.5. Females were significantly younger than males at presentation (p=0.025) by 8.8±3.8 years. Forty cases (60.6%) were located on the digits, 24 in nonvisceral soft tissue of extremities, trunk, and lip (36.4%), and one each in stomach and breast parenchyma. Sixty-three (95.5%) were benign (of which one recurred locally), 2 (3%) were malignant, and 1 (1.5%) was atypical. Four (6%) were multicentric. One case showed mixed histology (oncocytic and classic features) and one was classified as glomangiomatosis. The malignant cases each presented with a single tumor in lower extremity soft tissue in female patients (aged 33 and 49 years). The tumors measured 0.5 and 1.8 cm respectively and showed marked cytologic atypia in both and increased mitotic activity in the first. They were both completely excised. Conclusion The majority of glomus tumors are benign, however 3% are malignant. The most common location is the digits, followed by soft tissue. This tumor is more commonly seen in female patients. Unusual histologic variants such as glomangiomatosis and oncocytic component at times may create some difficulty to reach the diagnosis, especially on small biopsies. Unusual locations such as stomach can lead to a wrong diagnosis such as carcinoid, especially in a small biopsy material.

Survival and Recurrence in Pancreatobiliary Versus Intestinal Histology of Ampullary Carcinoma

Background: Ampullary carcinoma is rare with a more favourable prognosis compared to pancreatic ductal adenocarcinoma. The role of histological classification, including pancreatobiliary (PB) and intestinal (INT), on survival and recurrence outcomes in ampullary cancer is still debatable. Methods: 42 patients were identified between 1996-2010. Results: Nineteen classic pancreatoduodenectomies (PD) and 23 pylorus-preserving PDs were performed. Pathological review revealed 23, 18 and 1 patients with the PB, INT and mixed histology, respectively. Adjuvant chemoradiation (ACRT), chemotherapy, and radiation were given to 14 (33.3%), 4 (9.5%) and 2 (4.8%) patients, respectively. Recurrence-free survival (RFS) and overall survival (OS) from time of surgery were higher in the PB histological variant compared to INT (p=0.005 and 0.012, respectively). A landmark (LM) analysis found higher survival in the PB variant patients compared to INT (RFS p=0.023; OS p=0.048). There was no difference in RFS between both histological variants for patients who underwent surgery alone (p=0.42). However, the PB had higher RFS compared to the INT histology for patients who underwent ACRT (p=0.008). Conclusion: Ampullary carcinoma with PB histological variant was associated with significant survival benefit. The PB versus INT survival benefit was seen in the setting of ACRT, but not with surgery alone.

A Network Meta-Analysis of Cancer Immunotherapies Versus Chemotherapy for First-Line Treatment of Patients With Non-Small Cell Lung Cancer and High Programmed Death-Ligand 1 Expression

In the absence of head-to-head trials of first-line treatments for metastatic non-small cell lung cancer (NSCLC), synthesis of available evidence is needed. We conducted a systematic literature review and network meta-analysis of randomized controlled trials in patients with stage IV NSCLC and high programmed death-ligand 1 (PD-L1) expression. Patients with other-stage NSCLC or without PD-L1 expression and populations with < 80% stage IV NSCLC were excluded. Outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and treatment-related adverse events. English records from MEDLINE and Embase published through October 2020 were eligible, supplemented by hand searches of other sources. Three evidence networks were constructed based on histology (mixed, squamous, non-squamous). OS and PFS results were analyzed applying Bayesian fractional polynomial random-effects models. Hazard ratios over time with 95% credible intervals (CrIs) and expected differences in OS and PFS between each cancer immunotherapy regimen and the chemotherapy common comparator were generated. Seventeen clinical trials were included after screening 32,527 records. Heterogeneity and risk of bias were generally low across trials. In the mixed-histology network of PD-L1–high patients, expected OS was significantly longer with atezolizumab (estimated difference: 10.4 months [95% CrI: 1.9, 18.2]), pembrolizumab (7.2 [2.2, 12.3]), and cemiplimab (13.0 [4.2, 21.0]) versus chemotherapy but not with nivolumab (3.5 [−2.5, 10.6]) or nivolumab plus ipilimumab (6.7 [−0.5, 14.2]) versus chemotherapy. OS improvements were not significant compared with chemotherapy for any regimen in the squamous and non-squamous networks, except pembrolizumab plus chemotherapy in the non-squamous network. All regimens showed significantly longer expected PFS versus chemotherapy in the non-squamous network, whereas the increases were not significant in the mixed or squamous networks. ORR was significantly higher with pembrolizumab and cemiplimab versus chemotherapy in the mixed-histology network, with sintilimab in the non-squamous network, and with combination regimens, including pembrolizumab or atezolizumab, in the squamous and non-squamous networks, except with atezolizumab plus carboplatin, paclitaxel, and bevacizumab. Survival and safety versus chemotherapy were generally similar across cancer immunotherapies and histology networks. These findings may support treatment decisions for patients with high PD-L1 status receiving first-line treatment for NSCLC.

Immune checkpoint inhibitors (ICI) in advanced sarcomatoid renal cell carcinoma (sRCC): A multicenter study.

4568 Background: Advanced sRCC is an aggressive disease with limited responsiveness to chemotherapy and VEGF-targeted therapies. Subgroup analyses from randomized trials showed improved outcomes with ICI, though sample sizes were relatively small. Methods: We conducted a multi-institutional retrospective analysis of consecutive patients (pts) who had RCC with any sarcomatoid component and received systemic therapy for advanced disease. The pts were classified into ICI+ and ICI- groups (gp) based on whether they had received ICI in any treatment line. Overall survival (OS) was measured from the initiation of first systemic therapy. Time to ICI failure (TIF) was defined as the interval from initiation of ICI to subsequent therapy or death. Survival distributions were estimated using the Kaplan-Meier method. Association between covariates and survival was analyzed using multivariate Cox regression. Two-tailed P < 0.05 was considered statistically significant. Results: 203 pts from 6 US academic cancer centers met the inclusion criteria – 155 in ICI+ gp and 48 in ICI- gp. Overall, 137 (67%) pts were male and 181 (89%) were white; median age at mRCC diagnosis was 59.7 (IQR 52.4-67.7) years; 129 (63%) pts presented de novo with distant metastases, 154 (76%) had clear cell (CC) histology, and 182 (90%) had intermediate/poor risk by IMDC criteria. ICI+ had a higher proportion of purely CC tumors (81% vs 64%, P =.02); other demographic and clinical features were similar between the two gps. After a median follow-up of 48.1 (95% CI 40.7-55.5) months (mos), median OS and response rates were significantly higher in the ICI+ gp (Table). OS benefit, compared to ICI-, was maintained in pts who received ICI in ≥ second line (39.6 vs 7.6 mos, HR 0.33, 95% CI 0.22-0.51, log-rank P <.001). TIF was comparable between pts treated with ICI upfront vs in ≥ second line (6.0 vs 5.3 mos, HR 1.27, 95% CI 0.87-1.85, P =.21). On multivariate analysis, ICI- (HR 2.50, 95% CI 1.61-3.88, P <.001), non-CC histology (HR 3.14, 95% CI 1.98-5.00, P <.001) and sarcomatoid component ≥20% (HR 1.92, 95% CI 1.28-2.90, P =.002) were predictive of all-cause mortality. Among pts with non-CC or mixed histology (n=45), ICI+ had higher OS (18.0 vs 5.5 mos, HR 0.20, 95% CI 0.09-0.44, P <.001) and ORR (44% vs 12%, P =.03), compared to ICI-. Conclusions: Treatment with ICI led to markedly higher survival and response rates in advanced sRCC. OS benefit was maintained with ICI in the second line and beyond. Significant benefit was also noted among pts with non-CC or mixed histology sRCC.[Table: see text]

Breast Cancer Prevalence and Management in Hispanic Women: Comparison to Black and White Women at a Regional Medical Center

Background: While stage and grade of breast cancer determines prognosis and outcome, race also impacts survival. While Black and White women have been studied, data for Hispanic women is sparse. Methods: Age-matched Hispanic, Black and White women diagnosed/treated with breast cancer at a single institution were retrospectively evaluated regarding prevalence, treatments and outcomes. Results: Overall, 120 women were included in the study (40 per race). No demographic/histologic variables were significantly different among races. ER+/PR+ tumors were less frequent in Hispanics than Whites, but higher than Blacks. Prevalence of triple negative breast cancers in Hispanic women was between the Black and White cohorts (p=0.025 and p=0.011, respectively). Stage II and III diagnoses (p=0.025) were more frequent in Hispanics and they opted for chemotherapy more often (p=0.034); however, there were no significant differences in outcomes and mortality among groups. When compared to the State tumor registry, our population had more LCIS diagnoses (p=0.01), earlier stages (I p=0.02; II p=0.006), received more treatment overall (radiation p=0.02, chemotherapy p=0.0001) and experienced better survival (p=0.004). In comparing the study population to the SEER database, higher rates of LCIS and IDC and lower rates of ILC and mixed histology in the study population were noted. LCIS and IDC were more prevalent in our cohort than SEER data (p=0.005, p=0.05, respectively), although we noted less ILC and mixed histology (p=0.03 and p=0.04). Conclusion: These data are the first reported for Hispanics in our state and highlight the need for larger studies to better serve this growing demographic.

Immune checkpoint inhibitors (ICI) in advanced upper tract and lower tract urothelial carcinoma (UC): A comparison of outcomes.

406 Background: Despite anatomical and biological differences, upper and lower tract UC (UTUC; LTUC) are usually managed similarly. Modern era clinical trial data comparing their outcomes with ICI are conflicting. We hypothesized that response and outcomes would be similar in patients (pts) with advanced UTUC and LTUC. Methods: We performed a retrospective cohort study collecting demographic, clinicopathologic, treatment, and outcome data for pts with advanced UC receiving ICI (2013-2020) across 24 centers (US; Europe). We compared objective response rate (ORR), overall survival (OS), and progression-free survival (PFS) between pts with UTUC and LTUC. Uni- / multi- variable logistic and Cox regression were used to assess the effect of UTUC on ORR, OS, and PFS. Stratified subgroup analyses were performed according to histology (pure, mixed) and line of treatment (first-line, subsequent). Results: A total of 984 pts were identified, and 707, 717, and 738 were included in ORR, OS, and PFS analyses, respectively. After exclusions, the UTUC group comprised of 130 pts (vs. 616 in LTUC) with median age 71 (40-92) (vs. 70 [32-93]), 62% men (vs. 76%), 41% never smokers (vs. 29%), 62% with history of prior radical surgery for primary tumor (vs. 52%), and 29% with liver metastases (vs. 18%). Table shows results of ORR, OS, and PFS analyses. In the overall population, pts with UTUC and LTUC receiving ICI had comparable ORR, OS, and PFS. Pts with mixed-histology UTUC had significantly lower ORR (adjusted OR 0.20, 95%CI 0.05-0.91) and shorter PFS (adjusted HR 1.66, 95%CI: 1.06-2.59) vs. mixed-histology LTUC. Conclusions: Pts with advanced UTUC and LTUC receiving ICI have similar response and outcomes, except for pts with mixed-histology UTUC vs LTUC. Subset analysis of primary tumor location in ongoing clinical trials can validate our data, while biomarker work is ongoing. [Table: see text]

Genomic landscape of variant urinary tumor histologies.

467 Background: The genetics of urothelial carcinoma (UC), the most common histology of urinary tract (UT) tumors, is well characterized; much less is known about the genomic features of rare histologic variants of UT tumors. We aim to compare the genomic alterations (GA) of UT tumors with adenocarcinoma (AD), small cell (SC), squamous cell (SQ), or plasmacytoid (PC) histologies, to UC tumors. Methods: We identified patients with pure variant (AD, SC, SQ, PC) or UC histology with genetic characterization through the GENIE registry. Patient tumor genomic data were captured by Memorial Sloan Kettering Cancer Center (MSK)-IMPACT and Dana-Farber Cancer Institute (DFCI)-Oncopanel NGS initiatives. Tumors with mixed histology were excluded. We limited our analysis to genes tested >1000 times (N=211). Mutation frequencies and copy number variants (CNVs), collectively called GAs, were determined for AD, SC, SQ, PC, and UC, and were compared using the Fisher’s Exact test and Kruskall Wallis test. Nominal p values were obtained, and FDR correction was employed (q < 0.1). Results: We identified 1199 patients with available genomic data who met the inclusion criteria. Histologic distribution was: 32 AD, 13 SC, 15 SQ, 11 PC, and 1128 UC tumors. The median age was 68 years and 77% of patients were male. Statistically significant differences in genetic alterations by subtype are shown in the table below. ARID1A and KDM6A GAs were higher in UC; PC and SC; CDH1 GAs higher in PC; RB1 and TP53 GAs higher in SC; SMAD4 GAs higher in AD; and NFE2L2 GAs higher in SQ. Conclusions: Variant UT histologies exhibit a distinct pattern of alterations compared to UC, consistent with their divergent clinical behavior. This suggests different biological origins for these variant histologies and possibly different therapeutic vulnerabilities. Exploring the GAs of these UT tumors in larger datasets is warranted. [Table: see text]