Impact of PIPAC-Oxaliplatin on Functional Recovery, Good Days, and Survival in a Refractory Colorectal and Appendiceal Carcinomatosis: Secondary Analysis of the US PIPAC Collaborative Phase 1 Trial.

BACKGROUND: Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel, minimally invasive, safe, and repeatable method to treat carcinomatosis. Evidence regarding the clinical benefit (quality of life and survival) of PIPAC compared with that of conventional standard therapy (ST) is lacking. METHODS: This is the secondary analysis of the phase 1 US-PIPAC trial for refractory colorectal and appendiceal carcinomatosis. A PIPAC cohort was compared with a retrospective cohort of consecutive patients receiving ST. The primary outcome was number of good days (number of days alive and out of the hospital). The secondary outcomes were overall survival (OS), progression-free survival (PFS), health-related quality of life (HRQoL), and objective functional recovery (daily step count). RESULTS: The study included 32 patients (PIPAC, 12; ST, 20) with similar baseline characteristics. Compared with the ST cohort, the PIPAC cohort had lower median inpatient hospital stays (> 24 h) within 6 months (0 vs 1; p = 0.015) and 1 year (1 vs 2; p = 0.052) and higher median good days at 6 months (181 vs 131 days; p = 0.042) and 1 year (323 vs 131 days; p = 0.032). There was no worsening of HRQoL after repeated PIPACs. Step counts diminished immediately after PIPAC but returned to baseline within 2-4 weeks. Kaplan-Meier analysis demonstrated a favorable association between receipt of PIPAC and OS (median, 11.3 vs 5.1 months; p = 0.036). CONCLUSION: Compared with ST, PIPAC was associated with higher number of good days, reduced hospitalization burden, and longer OS without a negative impact on HRQoL with repeated PIPACs. These findings are foundational for evaluation of PIPAC in a randomized clinical trial.

Minorities Face Delays to Pancreatic Cancer Treatment Regardless of Diagnosis Setting.

INTRODUCTION: Our analysis was designed to characterize the demographics and disparities between the diagnosis of pancreas cancer during emergency presentation (EP) and the outpatient setting (OP) and to see the impact of our institutions pancreatic multidisciplinary clinic (PMDC) on these disparities. METHODS: Institutional review board-approved retrospective review of our institutional cancer registry and PMDC databases identified patients diagnosed/treated for pancreatic ductal adenocarcinoma between 2014 and 2022. Chi-square tests were used for categorical variables, and one-way ANOVA with a Bonferroni correction was used for continuous variables. Statistical significance was set at p < 0.05. RESULTS: A total of 286 patients met inclusion criteria. Eighty-nine patients (31.1%) were underrepresented minorities (URM). Fifty-seven (64.0%) URMs presented during an EP versus 100 (50.8%) non-URMs (p = 0.037). Forty-one (46.1%) URMs were reviewed at PMDC versus 71 (36.0%) non-URMs (p = 0.10). No differences in clinical and pathologic stage between the cohorts (p = 0.28) were present. URMs took 22 days longer on average to receive treatment (66.5 days vs. 44.8 days, p = 0.003) in the EP cohort and 18 days longer in OP cohort (58.0 days vs. 40.5 days, p < 0.001) compared with non-URMs. Pancreatic Multidisciplinary Clinic enrollment in EP cohort eliminated the difference in time to treatment between cohorts (48.3 days vs. 37.0 days; p = 0.151). RESULTS: Underrepresented minorities were more likely to be diagnosed via EP and showed delayed times to treatment compared with non-URM counterparts. Our PMDC alleviated some of these observed disparities. Future studies are required to elucidate the specific factors that resulted in these findings and to identify solutions.

A Palliative Care Curriculum May Promote Resident Self-Reflection and Address Moral Injury.

INTRODUCTION: There is a lack of formal palliative care education for surgical trainees, and the demanding nature of surgical training and exposure to challenging clinical scenarios can contribute to moral injury. We developed a palliative care curriculum to promote self-reflection, aiming to address moral injury in residents. METHODS: Five 1-h palliative care sessions were delivered over the academic year to all post-graduate year (PGY) levels covering the following topics: personal awareness, delivering bad news, surgical palliation for cancer pathology, surgical palliation for noncancer pathology, and urgent palliative care. The curriculum focused on reflection and small group discussions. The Moral Injury Symptom Scale-Health Professional was administered to assess feelings of moral injury. Descriptive statistics, chi-squared analysis, and Mann-Whitney U-test were used to compare the demographics and survey responses. RESULTS: 23 participants completed the preintervention survey, and 9 participants completed it postintervention. Over 50% of participants were PGY1 or PGY2 residents. Preintervention, 52% of participants reported feeling guilt over failing to save someone from being seriously injured or dying. 30% of participants reported that the feelings of guilt, shame, or distrust impaired their ability to function in relationships, at work, or other areas of life to at least a moderate degree. CONCLUSIONS: The described palliative care curriculum accomplishes several goals as follows: it educates residents on palliative care topics, teaches communication tools, encourages self-reflection, and provides space for building peer relationships. The ease of implementation makes this curriculum applicable across various types of institutions, offering the potential to positively impact surgical training on a national scale.

Modified 5-Item Frailty Index (mFI-5) may predict postoperative outcomes after pancreatoduodenectomy for pancreatic Cancer.

BACKGROUND: Pancreatic Ductal Adenocarcinoma (PDAC) primarily affects older individuals with diminished physiological reserves. The Modified 5-Item Frailty Index (mFI-5) is a novel risk stratification tool proposed to predict postoperative morbidity and mortality. This study aimed to validate the mFI-5 for predicting surgical outcomes in patients undergoing pancreatoduodenectomy (PD) for PDAC. METHODS: Our retrospective PDAC database included patients who underwent PD between 2014 and 2023. Patients were stratified by mFI-5 scores (0 best - 5 worst), which assess preoperative CHF, diabetes mellitus, history of COPD or pneumonia, functional health status, and hypertension requiring medication. Associations between mFI-5 scores and outcomes, including postoperative complications and mortality, were analyzed using logistic regression, Cox proportional hazards models, and Kaplan-Meier survival analysis. RESULTS: Among 250 PDAC patients undergoing PD, 142 (56.8%) had mFI-5 scores ≤ 1, and 25 (10%) had scores ≥ 3. No patients had scores > 4. Higher mFI-5 scores correlated with older age (p < 0.001) and tobacco use (p = 0.036). Multivariate analysis identified age (RR 1.02, p = 0.038), ASA class (ASA III; RR 2.61, p < 0.001; ASA IV; RR 2.63, p = 0.026), and moderate alcohol consumption (RR 0.56, p = 0.038) as frailty predictors. An mFI-5 score > 2 independently associated with higher mortality (HR 2.08, p = 0.026). Median overall survival was significantly lower for patients with mFI-5 scores > 2 than for those with scores ≤ 2 (21.3 vs. 42.1 months, p = 0.022). CONCLUSIONS: The mFI-5 is a valuable tool for predicting postoperative morbidity and mortality in PDAC patients undergoing PD. Integrating frailty assessment into preoperative evaluations can enhance patient selection and surgical outcomes. Future research should focus on incorporating frailty assessments into surgical planning and patient management to improve outcomes in this vulnerable population.

Outcomes of minimally invasive vs. open pancreatoduodenectomies in pancreatic adenocarcinoma: analysis of ACS-NSQIP data.

INTRODUCTION: Pancreatoduodenectomy (PD) for pancreatic adenocarcinoma (PDAC) presents a significant challenge owing to its aggressive nature. Traditionally performed as open surgery, the advent of minimally invasive surgery (MIS) including laparoscopic and robotic techniques, offers a potential alternative. This study assessed the use and outcomes of MIS and open PD for PDAC treatment. METHODS: We analyzed ACS-NSQIP data (2015-2021) using regression models to compare patient outcomes across open PD, MIS PD, and conversions from MIS to open (MIS-O). RESULTS: Of 19,812 PDAC patients, 1,293 (6.53%) underwent MIS, 18,116 (91.44%) underwent open PD, and 403 (2.03%) underwent MIS converted to open PD (MIS-O). The MIS rate increased from 6.1% to 9.2%. Black patients had a higher MIS-O rate (RR, 1.55; p = 0.025). Open PD was associated with more severe conditions (ASA ≥ III, malnutrition) and prior radiation therapy. MIS patients more often had neoadjuvant chemotherapy. Complex procedures, such as vein resection, favored open PD. Need for arterial resection was associated with MIS-O (RR, 2.11; p = 0.012), and operative time was significantly associated with MIS (OR: 4.32, 95% CI: 3.43-5.43, p-value: < 0.001) No differences in the overall morbidity or 30-day mortality were observed. MIS led to shorter stays but higher risks of reoperation and pulmonary embolism. MIS-O increased the delayed gastric emptying rate (RR, 1.79; p < 0.001). CONCLUSION: During 2015-2021, an increasing number of patients with PDAC are undergoing MIS PD. Morbidity and mortality did not differ between open and MIS PD. MIS was performed more frequently in patients with better nutritional status and lower ASA, or when vascular resection was not anticipated. In well selected patients, short-term outcomes of MIS and open PD seem similar.

Potential Role for Observation in Small Solid Pseudopapillary Neoplasm (SPN).

BACKGROUND: Solid pseudopapillary neoplasms (SPN) are rare tumors of the pancreas, typically affecting young women. Resection is the mainstay of treatment but is associated with significant morbidity and potential mortality. We explore the idea that small, localized SPN could be safely observed. METHODS: This retrospective review of the Pancreas National Cancer Database from 2004 to 2018 identified SPN via histology code 8452. RESULTS: A total of 994 SPNs were identified. Mean age was 36.8 ± 0.5 years, 84.9% (n = 844) were female, and most had a Charlson-Deyo Comorbidity Coefficient (CDCC) of 0-1 (96.6%, n = 960). Patients were most often staged clinically as cT2 (69.5%, n = 457) followed by cT3 (17.6%, n = 116), cT1 (11.2%, n = 74), and cT4 (1.7%, n = 11). Clinical lymph node and distant metastasis rates were 3.0 and 4.0%, respectively. Surgical resection was performed in 96.6% of patients (n = 960), most commonly partial pancreatectomy (44.3%) followed by pancreatoduodenectomy (31.3%) and total pancreatectomy (8.1%). In patients clinically staged as node (N0) and distant metastasis (M0) negative, occult pathologic lymph node involvement was found in 0% (n = 28) of patients with stage cT1 and 0.5% (n = 185) of patients with cT2 disease. The risk of occult nodal metastasis significantly increased to 8.9% (n = 61) for patients with cT3 disease. The risk further increased to 50% (n = 2) in patients with cT4 disease. CONCLUSIONS: Herein, the specificity of excluding nodal involvement clinically is 99.5% in tumors ≤ 4 cm and 100% in tumors ≤ 2 cm. Therefore, there may be a role for close observation in patients with cT1N0 lesions to mitigate morbidity from major pancreatic resection.

Safety and Efficacy of Oxaliplatin Pressurized Intraperitoneal Aerosolized Chemotherapy (PIPAC) in Colorectal and Appendiceal Cancer with Peritoneal Metastases: Results of a Multicenter Phase I Trial in the USA.

BACKGROUND: Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a laparoscopic locoregional treatment for peritoneal metastases (PM) from colorectal cancer (CRC) or appendiceal cancer (AC) in patients who cannot undergo cytoreductive surgery (CRS). While PIPAC has been studied in Europe and Asia, it has not been investigated in the USA. PATIENTS AND METHODS: We evaluated PIPAC with 90 mg/m2 oxaliplatin alone (cycle 1) and preceded by systemic chemotherapy with fluorouracil (5-FU) and leucovorin (LV) (cycle 2-3) as a multicenter prospective phase I clinical trial (NCT04329494). The primary endpoint was treatment-related adverse events (AEs). Secondary endpoints included survival and laparoscopic, histologic, and radiographic response. RESULTS: 12 patients were included: 8 with CRC and 4 with AC. Median prior chemotherapy cycles was 2 (interquartile range (IQR) 2-3). All patients were refractory to systemic oxaliplatin-based chemotherapy. Median peritoneal carcinomatosis index (PCI) was 28 (IQR 19-32). Six (50%) of twelve patients completed three PIPAC cycles. No surgical complications or dose-limiting toxicities were observed. Two patients developed grade 3 treatment-related toxicities (one abdominal pain and one anemia). Median overall survival (OS) was 12.0 months, and median progression-free survival (PFS) was 2.9 months. OS was correlated with stable disease by Response Evaluation Criteria in Solid Tumors (RECIST) criteria but not with laparoscopic response by PCI or histologic response by peritoneal regression grading system (PRGS). CONCLUSIONS: This phase I trial in the USA demonstrated safety, feasibility, and early efficacy signal of PIPAC with oxaliplatin and chemotherapy in patients with PM from AC or CRC who are refractory to standard lines of systemic chemotherapy.

Recovery of Skill Decay After COVID-19 Redeployments and Implications for Competency Attainment.

INTRODUCTION: The COVID-19 pandemic immediately interrupted procedural training. The lasting impact of reduced caseloads and service redeployments on procedural-resident training has been underexplored. This longitudinal study investigated the long-term perspectives of skill decay after short breaks in training and implications for ensuring resident competency attainment. METHODS: Web-based cross-sectional surveys distributed immediately after (June 2020) compared to 1 y after (July 2021) COVID-19 redeployments at two tertiary academic medical centers of an integrated health system in New York. Participants included general surgery, surgical subspecialty, and anesthesiology residents and faculty. RESULTS: Fifty-five residents and 33 faculty completed the survey. Ninety-point nine percent of residents and 36.4% of faculty were redeployed to COVID-ICUs. Sixty-three-point seven percent of residents and 75.0% of faculty reported a reduction in resident technical skills in the short-term, with significantly less (45.5% of residents and 21.2% of faculty) reporting persistent reduction in technical skill after 1 y (P = 0.001, P < 0.001). Seventy-five percent of residents and 100% of faculty were confident residents would be able to practice independently at the conclusion of their training. Sixty-five-point five percent of residents and 63.6% of faculty felt that residents experienced a durable improvement in critical care skills. Residents also reported a positive long-term impact on professional core competencies at 1 y. CONCLUSIONS: Longitudinal surveillance of residents after COVID-19 redeployments suggests washout of temporary skill decay and return of resident confidence upon resumption of traditional training. This may provide insight into the impact of other short-term training interruptions on resident skill and promote greater resident support upon training resumption to ensure competency attainment.

Surgical debulking is associated with improved survival for patients with neuroendocrine liver metastases of unknown primary.

BACKGROUND: Resection of neuroendocrine tumors (NET) with surgical debulking of liver metastasis (NETLM) is associated with improved survival. In patients with an unknown primary (UP-NETLM), the effects of debulking remains unclear. METHODS: The National Cancer Database (2004-2016) was queried for patients with small intestine (SI) and pancreas (P) NETLMs. If the liver was listed as the primary site, the patient's disease was classified as UP-NETLM. RESULTS: Patients with UP-NETLM, SI-NETLM, and P-NETLM who were managed non-operatively demonstrated a significant difference in 5-year overall survival (OS) (21.5% vs. 39.2% vs. 17.1%; p < 0.0001). OS in patients who underwent debulking was higher (63.7% vs. 73.2% vs. 54.2%). Patients with UP-NETLMs who underwent debulking had similar OS to patient with SI-NETLM (p = 0.051), but significantly higher OS, depending on tumor differentiation, compared to patients with P-NETLMs. If well-differentiated, surgery for UP-NETLMs was associated with a higher rate of OS (p = 0.009), while no difference was observed if moderately (p = 0.209) or poorly/undifferentiated (p = 0.633). P-NETLMs were associated with worse OS (p < 0.001) on multivariate analysis. DISCUSSION: Debulking in patients with UP-NETLMs was associated with similar OS compared to patients with SI-NETLMs and better or similar OS compared to patient with P-NETLMs.

Pancreatic Cancer Patient-derived Organoids Can Predict Response to Neoadjuvant Chemotherapy.

OBJECTIVE: To evaluate if patient-derived organoids (PDOs) may predict response to neoadjuvant (NAT) chemotherapy in patients with pancreatic adenocarcinoma. BACKGROUND: PDOs have been explored as a biomarker of therapy response and for personalized therapeutics in patients with pancreatic cancer. METHODS: During 2017-2021, patients were enrolled into an IRB-approved protocol and PDO cultures were established. PDOs of interest were analyzed through a translational pipeline incorporating molecular profiling and drug sensitivity testing. RESULTS: One hundred thirty-six samples, including both surgical resections and fine needle aspiration/biopsy from 117 patients with pancreatic cancer were collected. This biobank included diversity in stage, sex, age, and race, with minority populations representing 1/3 of collected cases (16% Black, 9% Asian, 7% Hispanic/Latino). Among surgical specimens, PDO generation was successful in 71% (15 of 21) of patients who had received NAT prior to sample collection and in 76% (39 of 51) of patients who were untreated with chemotherapy or radiation at the time of collection. Pathological response to NAT correlated with PDO chemotherapy response, particularly oxaliplatin. We demonstrated the feasibility of a rapid PDO drug screen and generated data within 7 days of tissue resection. CONCLUSION: Herein we report a large single-institution organoid biobank, including ethnic minority samples. The ability to establish PDOs from chemotherapy-naive and post-NAT tissue enables longitudinal PDO generation to assess dynamic chemotherapy sensitivity profiling. PDOs can be rapidly screened and further development of rapid screening may aid in the initial stratification of patients to the most active NAT regimen.

The Impact of Socioeconomic Deprivation on Clinical Outcomes for Pancreatic Adenocarcinoma at a High-volume Cancer Center: A Retrospective Cohort Analysis.

OBJECTIVE: To assess the impact of a granular measure of SED on pancreatic surgical and cancer-related outcomes at a high-volume cancer center that employs a standardized clinic pathway. SUMMARY OF BACKGROUND DATA: Prior research has shown that low socioeconomic status leads to less treatment and worse outcomes for PDAC. However, these studies employed inconsistent definitions and categorizations of socioeconomic status, aggregated individual socioeconomic data using large geographic areas, and lacked detailed clinicopathologic variables. METHODS: We conducted a retrospective cohort study of 1552 PDAC patients between 2008 and 2015. Patients were stratified using the area deprivation index, a validated dataset that ranks census block groups based on SED. Multivariable models were used in the curative surgery cohort to predict the impact of SED on (1) grade 3/4 Clavien-Dindo complications, (2) initiation of adjuvant therapy, (3) completion of adjuvant therapy, and (4) overall survival. RESULTS: Patients from high SED neighborhoods constituted 29.9% of the cohort. Median overall survival was 28 months. The rate of Clavien-Dindo grade 3/4 complications was 14.2% and completion of adjuvant therapy was 65.6%. There was no evidence that SED impacted surgical evaluation, receipt of curative-intent surgery, postoperative complications, receipt of adjuvant therapy or overall survival. CONCLUSIONS: Although nearly one-quarter of curative-intent surgery patients were from high SED neighborhoods, this factor was not associated with measures of treatment quality or survival. These observations suggest that treatment at a high-volume cancer center employing a standardized clinical pathway may in part address socioeconomic disparities in pancreatic cancer.

Ampullary Neuroendocrine Tumors: Insight into a Rare Histology.

BACKGROUND: Ampullary neuroendocrine tumors (NETs) make up < 1% of all gastroenteropancreatic NETs, and information is limited to case series. This study compares patients with ampullary, duodenal, and pancreatic head NETs. METHODS: The National Cancer Database (2004-2016) was queried for patients with ampullary, duodenal, and pancreatic head NETs. Survival was evaluated using Kaplan-Meier analysis and Cox regression. RESULTS: Overall, 872, 9692, and 6561 patients were identified with ampullary, duodenal, and pancreatic head NETs, respectively. Patients with ampullary NETs had more grade 3 tumors (n = 149, 17%) than patients with duodenal (n = 197, 2%) or pancreatic head (n = 740, 11%) NETs. Patients with ampullary NETs had more positive lymph nodes (n = 297, 34%) than patients with duodenal (n = 950, 10%) or pancreatic head (n = 1513, 23%) NETs. On multivariable analysis for patients with ampullary NETs, age (hazard ratio [HR] 1.03, p < 0.0001), Charlson-Deyo score of 2 (HR 2.3, p = 0.001) or ≥3 (HR 2.9, p = 0.013), grade 2 (HR 1.9, p = 0.007) or grade 3 tumors (HR 4.0, p < 0.0001), and metastatic disease (HR 2.0, p = 0.001) were associated with decreased survival. At 5 years, the overall survival (OS) for patients with ampullary, duodenal, and pancreatic head NETs was 59%, 71%, and 50%, respectively (p < 0.0001), whereas the 5-year OS for patients with ampullary, duodenal, and pancreatic head NETs who underwent surgery was 62%, 78%, and 76%, respectively (p < 0.0001). CONCLUSIONS: Ampullary NETs were more likely to present with high-grade tumors and lymph node metastases. Based on the clinicopathologic and survival data, ampullary NETs have a unique underlying biology compared with duodenal and pancreatic head NETs.

Cancer outcomes are independent of preoperative CA 19-9 in anatomically resectable pancreatic ductal adenocarcinoma: A retrospective cohort analysis.

BACKGROUND AND OBJECTIVES: Current guidelines recommend neoadjuvant therapy for pancreatic ductal adenocarcinoma (PDAC) patients with anatomically resectable tumors but elevated CA 19-9. However, this recommendation is based on data from anatomically resectable and borderline resectable PDAC patients. Therefore, we analyzed the association of preoperative CA 19-9 with oncologic outcomes in a cohort of anatomically resectable PDAC patients. METHODS: A single-institution PDAC database from 2007 to 2015 included patients who underwent guideline-based staging and were anatomically resectable. Patients with bilirubin above 1.5 after decompression, nonsecretors of CA 19-9, and borderline resectable patients were excluded. Statistical analysis included frequency testing and regression modeling for recurrence and survival. RESULTS: One hundred forty-four PDAC patients were identified; 16 (11.1%) had elevated preoperative CA 19-9 ≥ 1000. A CA 19-9 level ≥1000 was not associated with demographic, clinical, or pathological factors. After adjustment for potential confounders, CA 19-9 levels (continuous, median, 500 U/mL, or 1000 U/mL cut-offs) were not associated with recurrence or overall survival (OS). CONCLUSIONS: Although guidelines recommend CA 19-9 to determine the management of anatomically resectable PDAC patients, CA 19-9 was not associated with recurrence or OS in this cohort. Our findings do not suggest that CA 19-9 alone should determine the PDAC treatment strategy.

Completion of adjuvant therapy in patients with resected pancreatic cancer.

BACKGROUND: Adjuvant chemotherapy is the standard of care for resected pancreatic ductal adenocarcinoma (PDAC). It is estimated that only 40-80% eligible patients initiate intended adjuvant chemotherapy. Completion rates are largely unknown. METHODS: A retrospective analysis of outcomes of patients with resected PDAC over an 8-year period at H. Lee Moffitt Cancer Center (MCC) was performed. RESULTS: From a total of 309 patients, 299 were included for further analysis. 242 (81%) initiated adjuvant therapy (AT) and 195 (65%) completed the intended course. The median time-to-initiation of AT was 53 days (7.6 weeks). The most common reasons for early discontinuation of AT (n = 47) were toxicity (n = 29), disease recurrence (n = 9), patient decision (n = 4), unrelated comorbidities (n = 3), and death (n = 1). Completion of AT was an independent predictor of overall survival (OS) and recurrence-free survival (RFS) on multivariable analysis (OS: HR 0.41, CI 0.27-0.61, p < 0.001; RFS: HR 0.52, CI 0.36-0.76, p < 0.001). Factors associated with early termination of AT were vascular resection (OR 0.29, CI 0.13-0.67, p = 0.004) and administration of AT with local oncologist as opposed to MCC (OR 0.41, CI 0.21-0.82, p = 0.010). CONCLUSION: Completion of AT is associated with improved survival in patients with resected PDAC. Factors associated with an inability to complete AT include vascular resection and administration of AT with local care team in the patient's community.

Molecular subclasses of hepatocellular carcinoma predict sensitivity to fibroblast growth factor receptor inhibition.

A recent gene expression classification of hepatocellular carcinoma (HCC) includes a poor survival subclass termed S2 representing about one-third of all HCC in clinical series. S2 cells express E-cadherin and c-myc and secrete AFP. As the expression of fibroblast growth factor receptors (FGFRs) differs between S2 and non-S2 HCC, this study investigated whether molecular subclasses of HCC predict sensitivity to FGFR inhibition. S2 cell lines were significantly more sensitive (p < 0.001) to the FGFR inhibitors BGJ398 and AZD4547. BGJ398 decreased MAPK signaling in S2 but not in non-S2 cell lines. All cell lines expressed FGFR1 and FGFR2, but only S2 cell lines expressed FGFR3 and FGFR4. FGFR4 siRNA decreased proliferation by 44% or more in all five S2 cell lines (p < 0.05 for each cell line), a significantly greater decrease than seen with knockdown of FGFR1-3 with siRNA transfection. FGFR4 knockdown decreased MAPK signaling in S2 cell lines, but little effect was seen with knockdown of FGFR1-3. In conclusion, the S2 molecular subclass of HCC is sensitive to FGFR inhibition. FGFR4-MAPK signaling plays an important role in driving proliferation of a molecular subclass of HCC. This classification system may help to identify those patients who are most likely to benefit from inhibition of this pathway.