Bartolini, Michela

3593 Background: CUB domain-containing protein 1 (CDCP1) is a transmembrane protein shown to be over-expressed in colorectal cancer (CRC), with an important role in tumor initiation, growth and metastasis. Through interactions with EGFR, CDCP1 promotes nuclear translocation of the key regulators of Wnt signaling, β-catenin and E-cadherin. High CDCP1 expression has been associated with poor survival outcomes in multiple solid tumors but data in CRC remains limited. We investigated associations between CDCP1 level and survival outcomes in patients with metastatic CRC (mCRC) in the phase III clinical trial CALGB/SWOG 80405 (Alliance). Methods: Data from 433 mCRC patients in the CALGB/SWOG 80405 (Alliance) trial were analyzed. Patients received bevacizumab (n = 226) or cetuximab (n = 207) plus chemotherapy as 1st-line treatment. Tumor RNA was extracted from FFPE samples and processed through the HiSeq 2500 (Illumina) platform. Overall survival (OS) and progression free survival (PFS) curves were evaluated in all treatment subgroups and stratified according to high or low CDCP1 expression. Likelihood ratio tests, hazard ratios (HRs), and 95% confidence intervals (CIs) were calculated using Cox proportional hazards multivariate models, adjusting for age, sex, ECOG performance status, tumor location, number of metastatic sites, KRAS status, consensus molecular subtypes, and treatment arm. Results: Overall, low CDCP1 expression was associated with better OS compared to high expression (HR = 1.38; 95% CI 1.07-1.77; 35.8 vs 25.0 months, p = 0.045). Subgroup analysis re-demonstrated this pattern in males (HR = 1.64; 95% CI 1.64-2.28; 35.9 vs 23.6 months, p = 0.01), patients with MSS tumors (HR = 1.56; 95% CI 1.17-2.08; 36.7 vs 25.1 months, p = 0.0094), and patients treated with cetuximab+FOLFOX (HR = 1.79; 95% CI 1.16-2.77; 40.8 vs 24.0 months, p = 0.03). The effect of CDCP1 expression on PFS was less pronounced. Relative to high expression, low expression was associated with better PFS in males (HR = 1.49; 95% CI 1.10-2.03; 13.1 vs 9.8 months, p = 0.027) and left-sided tumors (HR = 1.50; 95% CI 1.10-2.04; 14.4 vs 10.1 months, p = 0.034). Conclusions: Our findings represent real-world data of the predictive role of CDCP1 in patients with mCRC undergoing anti-EGFR or anti-VEGF treatment. Consistent with studies of other cancers, we show that low CDCP1 expression is predictive of better survival outcomes, with subgroup analysis revealing associations in males, MSS tumors, and left-sided tumors. Among treatment groups, low CDCP1 expression is predictive of better OS in cetuximab+FOLFOX-treated patients, a key finding given CDCP1’s close mechanistic ties to EGFR. Further studies should explore whether these associations are seen in other treatment modalities and whether CDCP1 blockade could represent a viable strategy in patients with high expression.

Abstract Introduction: Fibroblast growth factor receptor 2 and 3 (FGFR2 and FGFR3) are metabolic genes overexpressed in malignant epithelia. In colorectal cancer (CRC), intimate crosstalk between FGFR2/3 and epidermal growth factor receptor (EGFR) pathways has been suggested but is not fully elucidated. As a result, this study investigated associations between FGFR2/3 expression levels and clinical outcomes in patients with metastatic CRC (mCRC) enrolled in the phase III clinical trial CALGB /SWOG 80405. Methods: Data from 433 patients with mCRC enrolled in the CALGB/SWOG 80405 trial were analyzed. Patients received either bevacizumab (bev, n = 226) or cetuximab (cet, n = 207) plus chemotherapy as first-line treatment. Tumor RNA was extracted from FFPE samples and processed through the HiSeq 2500 (Ilumina) platform. Median overall survival (OS) and progression-free survival (PFS) curves were evaluated in all treatment subgroups and stratified according to high (H), medium (M), and low (L) FGFR 2 and 3 gene expression levels. Likelihood ratio tests, hazard ratios (HRs), and 95% confidence intervals (CIs) were calculated using Cox proportional hazards multivariate models, adjusting for age, sex, ECOG performance status, tumor location, number of metastatic sites, KRAS status, consensus molecular subtypes, and treatment arm. Results: Both FGFR2 and FGFR3 expression levels were associated with outcomes in patients treated with cetuximab. FGFR2-L tumors showed significantly longer OS compared to the M (HR = 1.04; 95%CI 0.71-1.51) and H (HR = 1.56; 95%CI 1.06-2.28) expression groups (35.7 vs. 31.2 vs. 23.7 months, p = 0.017). In contrast, FGFR3-L tumors were associated with shorter OS compared to the M (HR = 0.63; 95%CI 0.44-0.92) and H (HR = 0.59; 95%CI 0.41-0.85) expression groups (24.7 vs 32.4 vs 37.1 months, p = 0.0009). Significant differences in PFS were not observed. A nominally significant interaction was found between treatment and FGFR3 expression for both PFS (p = 0.02) and OS (p = 0.0003), but no interaction with FGFR2 expression. No significant associations were detected in patients treated with bev. Neither FGFR2 nor FGFR3 suggested to be prognostic markers after multivariate adjustment analyses. Conclusions: Our findings suggest a predictive role of FGFR3 in patients with mCRC undergoing anti-EGFR treatment. Differences in survival within the cet subgroup suggest that EGFR inhibitor efficacy may be modulated by FGFR2/3 signaling activity. Interestingly, FGFR2 and FGFR3 expressions were inversely and positively correlated with improved OS. The findings suggest that FGFR2 signaling minimizes the specific effects of cetuximab, while FGFR3 signaling amplifies its therapeutic effects. Further studies should determine whether these associations are seen in other anti-EGFR inhibitors and detail the mechanistic interaction between FGFR and EGFR pathways. Citation Format: Steve Soto Trujillo, Yan Yang, Michela Bartolini, Shivani Soni, Pooja Mittal, Fang-Shu Ou, Lesly Torres-Gonzalez, Unnati Hemant Shah, Jae Ho Lo, Yitzhar Goretsky, Wu Zhang, Alan Venook, Sandra Algaze, Joshua Millstein, Heinz-Josef Lenz. Differences in survival outcomes among metastatic colorectal cancer patients across fibroblast growth factor receptor 2 and 3 expression levels [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6751.

Abstract Background. Mitophagy plays a crucial role in removing dysfunctional mitochondria to maintain cellular homeostasis but also has been implicated in cancer tumorigenesis. Previously, we showed that genetic variation in mitophagy pathway genes holds a predictive value in metastatic CRC (mCRC) patients (pts) treated with bevacizumab-based chemotherapy. In this study, we analyzed the correlation between tumor expression profiles of genes associated with PINK1/Parkin and BNIP3/NIX/FUNDC1 mitophagy pathways with clinical outcome in a large phase III randomized clinical trial CALGB SWOG 80405. Method. We analyzed 433 pts with mCRC treated with first-line chemotherapy in combination with the targeted agents bevacizumab (Bev, n = 226) or cetuximab (Cet, n = 207). Tumor RNA isolated from FFPE samples was sequenced using the HiSeq 2500 platform (Illumina). Median Overall survival (mOS) and median progression-free survival (mPFS) were compared across pts groups divided into high, medium, and low tertiles based on mitophagy-related gene (BNIP3, BNIP3L, PINK1, PRKN) expression levels. Likelihood ratio tests, hazard ratios (HRs), and 95% confidence intervals (CIs) were calculated using multivariable Cox proportional hazards models, adjusting for age, sex, ECOG performance status, tumor location, number of metastatic sites, KRAS status, Consensus Molecular Subtypes, and treatment arm. Results: Overall, BNIP3L demonstrated significant prognostic value for both PFS and OS after adjustment for multiple testing (false discovery rate [FDR] < 0.05). Tumors with low BNIP3L expression showed longer PFS and OS compared to those with medium or high expression levels (mPFS 14.8 vs. 10.0 vs. 9.2 months, HR 1.16, 95% CI 1.04 - 1.29p = 0.0182; mOS: 37.4 vs. 30.2 vs. 24.4 months, HR 1.22, 95% CI 1.09 - 1.38, p = 0.0036), independent of treatment. In pts treated with Cet, high PRKN expression was associated with improved PFS and OS (mPFS: 8.9 vs. 10.3 vs. 14.6 months, HR 0.79; 95% CI 0.69 - 0.91, p = 7.3e-05; mOS: 21.2 vs. 27.7 vs. 41.1 months, HR 0.87; 95% CI 0.75 - 1.01, p = 0.00084), whereas low PINK1 expression was significantly associated with longer OS (mOS: 24.9 vs. 30.9 vs. 39.2 months, HR 1.23; 95% CI 1.04 -1.46, p = 0.013). No significant associations were observed in Bev-treated patients for PRKN or PINK1. No significant results were found for BNIP3 expression analysis. Conclusion. Mitophagy is a crucial player in CRC biology due to its tumor-intrinsic (mitochondrial bioenergetics) and microenvironment (interacts with immune components) effects. Our study highlights the prognostic value of BNIP3L and predictive potential of PINK1 and PRKN, suggesting a potential combinatorial therapeutic approach using mitochondrial targeting drugs and targeted agents e.g Cet, which warrants further investigation. Support: Genentech; Clinicaltrials.gov Identifier: NCT00265850 Citation Format: Shivani Soni, Yan Yang, Michela Bartolini, Pooja Mittal, Fang-Shu Ou, Lesly Torres-Gonzalez, Unnati Hemant Shah, Jae Ho Lo, Steve Soto Trujillo, Yitzhar Goretsky, Wu Zhang, Alan P. Venook, Sandra Algaze, Joshua Millstein, Heinz-Josef Lenz. Correlation of mitophagy related genes expression and clinical outcome in metastatic colorectal cancer patients enrolled in CALGB (Alliance)/SWOG 80405 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1011.

198 Background: The Hedgehog (Hh) signaling pathway regulates tissue patterning, growth and differentiation, including within gastrointestinal tract. Mammalian homologs include Sonic (SHH), Indian (IHH) and Desert (DHH) Hedgehog, which signal through PTCH and SMO and the GLI transcription factors. In the digestive tract, both SHH and IHH are expressed, but the functional role of Hh signaling in mCRC remains incompletely defined. Methods: We analyzed 433 mCRC patients treated with either bevacizumab (bev = 226) or cetuximab (cet = 207) plus first line chemotherapy in CALGB/SWOG 80405 (NCT00265850). RNA expression (Illumina HiSeq 2500) of 9 Hh pathway genes (SHH, IHH, DHH, PTCH1, PTCH2, SMO, GLI1, GLI2, GLI3) was evaluated. Median overall survival (mOS) and progression free survival (mPFS) in months (mo) were compared across expression tertiles (low [L], medium [M], high [H]). Likelihood ratio tests, hazard ratios and 95% confidence intervals were computed from multivariable Cox proportional hazards models, adjusting for age, sex, ethnicity, ECOG PS, tumor location, number of metastatic sites, KRAS , microsatellites instability status and treatment. Prognostic effects were modeled as marginal terms; predictive effects were modeled as multiplicative interactions. Results: Overall, IHH and GLI2 demonstrated prognostic value for OS after adjusting for multiple testing (Benjamini-Hochberg False Discovery Rate (FDR) < 0.05). High IHH expression (H group, n = 143) correlated with improved mOS (H: 36.0 mo vs M: 32.8 mo vs L: 23.5 mo; p= 0.031), whereas low GLI2 expression (L group, n = 145) was associated with longer mOS (H: 25.6 mo vs M: 33.9 mo vs L: 33.7 mo; p= 0.0016). Moreover, IHH showed predictive value for cet benefit in both OS (mOS H: 38.1 mo vs M: 34.0 mo vs L: 18.4 mo; p= 0.0032) and PFS (mPFS H: 12.6 mo vs M: 12.9 mo vs L: 8.8 mo; p= 0.0025) with significant treatment interaction for OS and PFS (p= 0.0046 and p= 0.0049, respectively; FDR< 0.05). No significant associations were found in bev treated pts. No other Hh genes showed significant prognostic or predictive effects after FDR correction. Conclusions: These results highlight a dual role of Hh pathway in mCRC. Consistent with prior preclinical evidence, reduced IHH expression appears to mark poor prognosis, likely reflecting the loss of IHH-mediated restraint on Wnt signaling, which drives proliferation and dedifferentiation. Conversely, low GLI2, a downstream transcription factor, was linked with favorable outcomes, underscoring context-specific effects of Hh signaling. The strong predictive association of IHH with cet efficacy supports its potential as a biomarker in RAS wild type mCRC. These results suggest that Hh pathway modulation, particularly IHH signaling, may influence disease biology and treatment response. Validation in independent cohorts and mechanistic studies is warranted to clarify implications.

3145 Background: SnoRNAs are non-coding RNAs that primarily guide the chemical modification of ribosomal RNA. Emerging evidence suggests snoRNAs play critical roles in cancer, including CRC, by regulating cell proliferation, apoptosis and tumor progression. Aberrant snoRNA expression has been linked to CRC development and poor prognosis, offering potential as diagnostic biomarkers and therapeutic targets. We investigated whether the tumor expression levels of 3 types of snoRNAs (SCARNA, SNORA, SNORD) affect treatment response in pts enrolled in CALGB/SWOG 80405 (NCT00265850). Methods: 433 mCRC pts treated with bevacizumab (bev, n = 226) or cetuximab (cet, n = 207) in combination with first-line chemotherapy were analyzed. RNA was isolated from FFPE tumor samples and sequenced on the HiSeq 2500 (Illumina). 422 snoRNAs were evaluated (23 SCARNA, 140 SNORA, 259 SNORD). Overall survival (OS) and progression-free survival (PFS) were compared across tertiles of gene expression (high [H], medium [M], low [L]) by multivariable Cox proportional hazards models adjusted for age, sex, ECOG performance status, tumor side, number of metastatic sites, KRAS , CMS subtypes, and treatment. Interaction tests for the predictive effect (bev vs cet) were performed. P -values were corrected for multiple testing using the Benjamini-Hochberg approach ( q < 0.05). Results: Only SCARNA21 achieved statistical significance for OS after false discovery rate (FDR) adjustment. Tumors with H levels of SCARNA21 had shorter survival compared to tumors with M or L expression (median OS 24.4 vs 32.4 vs 33.9 months, respectively; P = 0.0015, q = 0.033), independent of treatment. No snoRNAs achieved FDR significance for PFS. However, several snoRNAs showed significant treatment interactions with biologic agents. SCARNA6-H and SCARNA5-H tumors had longer PFS and OS when treated with cet, but shorter PFS and OS when treated with bev, compared to the M and L expression groups (PFS interaction q = 0.0067 and 0.045, respectively; OS interaction q = 0.022 and 0.034, respectively). SCARNA7 also showed significant treatment interaction for OS, favoring cet in the H expression group ( q = 0.018); the opposite was observed for SNORA63B, SNORA63D, SNORA35B, and SNORA36C ( q = 0.027, 0.027, 0.027 and 0.047, respectively). No significant results were observed for any of the tested SNORDs. Conclusions: SnoRNAs dysregulation affects key pathways such as cell cycle control and immune evasion, making them promising players in CRC biology. Our study highlights the prognostic and predictive potential of specific snoRNAs in mCRC. Notably, high SCARNA21 expression was linked to shorter OS, while SCARNA5 and 6 showed predictive value for treatment response, indicating their potential for guiding treatment decisions. Further validation is needed to confirm these findings, and mechanistic studies are warranted.

3128 Background: LncRNAs have emerged as key regulators of cancer progression and therapeutic responses. In CRC, several lncRNAs have been implicated in modulating tumor growth, metastasis and treatment resistance by interacting with critical tumorigenic pathways. Here, we investigate the potential prognostic and predictive value of lncRNA expression in patients (pts) with mCRC enrolled in CALGB/SWOG 80405 (NCT00265850) trial. Methods: We analyzed 433 mCRC pts treated with either bevacizumab (bev, n = 226) or cetuximab (cet, n = 207) plus first-line chemotherapy. Tumor RNA expression (Illumina HiSeq 2500) of 13 candidate lncRNAs (SNHG11, HOTAIR, FGF14-AS2, H19, YWHAE, NEAT1, MIR100HG, UCA1, LINC00973, SLCO4A1-AS1, POU5F1P4, MALAT1, HCG18) was explored. Median overall survival (mOS) and progression-free survival (mPFS) in months (mo) were compared between pts grouped by tertiles (low [L] vs medium [M] vs high [H]) of gene expression. Likelihood ratio tests, hazard ratios and 95% confidence intervals were computed from multivariable Cox proportional hazards models, adjusting for age, sex, ECOG PS, tumor location, number of metastatic sites, KRAS , Consensus Molecular Subtypes (CMS), and treatment. Results: Overall, SNHG11 was strongly associated with OS and PFS after adjusting for multiple tests (Benjamini-Hochberg False Discovery Rate < 0.05). High SNHG11 expression (H group, n = 144) was associated with improved mPFS (H: 14.3 vs M: 11.2 vs L: 8.3 mo; p = 0.038) and mOS (H: 39.6 vs M: 31.1 vs L: 20.5 mo; p = 0.033) in the combined treatment analysis. Among cet-treated pts, SNHG11-H showed a numerically longer mPFS (H: 14.2 vs M: 11.1 vs L: 7.6 mo; p = 0.19) and significantly longer mOS (H: 41.1 vs M: 32.4 vs L: 14.3 mo; p = 0.012). In contrast, no statistically significant OS or PFS differences were observed in bev-treated pts. SNHG11-H tumors had a significant OS benefit from cet compared to bev (mOS 41.1 vs 36.5 mo, respectively; p = 0.016), with a nominally significant treatment interaction observed for OS (p = 0.030). No significant differences were observed in the L or M expression groups. Additional analyses showed that SNHG11 expression was high in the CMS2 (canonical) subtype and substantially lower in CMS1 (immune). Conclusions: LncRNA SNHG11 plays a significant role in CRC progression and metastasis via tumorigenic pathways, including c-Myc and HIF-1α. Moreover, elevated circulating SNHG11 levels show promise as a non-invasive biomarker for early CRC detection. In CALGB/SWOG 80405, high SNHG11 expression correlated with improved PFS and OS, particularly in cet-treated pts, supporting its role as a prognostic and predictive biomarker. Its strong association with CMS2 aligns with its reported involvement in c-Myc-driven pathways. Further validation is needed to confirm the clinical utility of this biomarker and elucidate underlying mechanisms.