The presence and extent of regional lymph node and distant metastasis are the most fatal prognostic factors in penile squamous cell carcinoma (PSCC). However, the available biomarkers and detailed mechanisms underlying the metastasis of PSCC remain elusive. Here, we explored the expression landscape of HOX genes in twelve paired PSCC tissues, including primary tumors, metastatic lymph nodes and corresponding normal tissues, and highlighted that HOXD11 was indispensable in the progression of PSCC. HOXD11 was upregulated in PSCC cell lines and tumors, especially in metastatic lymph nodes. High HOXD11 expression was associated with aggressive features, such as advanced pN stages, extranodal extension, pelvic lymph node and distant metastasis, and predicted poor survival. Furthermore, tumorigenesis assays demonstrated that knockdown of HOXD11 not only inhibited the capability of cell proliferation, invasion and tumor growth but also reduced the burden of metastatic lymph nodes. Further mechanistic studies indicated that miR-138-5p was a tumor suppressor in PSCC by inhibiting the translation of HOXD11 post-transcriptionally through binding to the 3′ untranslated region. Furthermore, HOXD11 activated the transcription of FN1 to decompose the extracellular matrix and to promote epithelial mesenchymal transition-like phenotype metastasis via FN1/MMP2/MMP9 pathways. Our study revealed that HOXD11 is a promising prognostic biomarker and predicts advanced disease with poor outcomes, which could serve as a potential therapeutic target for PSCC.

RAB20, a member of the RAS GTPase oncogene family, is overexpressed in several cancers with poor outcomes, promoting tumorigenesis and inducing genomic instability. Here, we performed comprehensive genomic sequencing on eight penile squamous cell carcinoma (PSCC) and normal tissue pairs and found that RAB20 was upregulated in tumors, especially in metastatic lymph nodes. RAB20 overexpression in tumors was further verified by qPCR, Western blotting, and immunohistochemistry of our newly established PSCC cell lines and paired tissues. The clinical significance of RAB20 was validated in 259 PSCC patients, the largest cohort to date, and high RAB20 expression positively correlated with the T, N, M status, extranodal extension, and clinical stage (all p < 0.01). RAB20 was an unfavorable independent prognostic indicator in the survival analysis (p = 0.011, HR = 2.090; 95% Cl: 1.183–4.692), and PSCC patients with high RAB20 expression experienced shorter 5-year cancer-specific survival times (p < 0.001). Furthermore, tumorigenesis assays demonstrated that RAB20 knockdown inhibited cell proliferation, migration, and colony formation in vitro and tumor growth in vivo. RAB20 depletion also induced PSCC cell cycle arrest at G2/M by increasing Chk1 expression and promoting cdc25c phosphorylation to reduce cdc2-cyclinB1 complex formation. Our study revealed an oncogenic role for RAB20 in promoting PSCC cell proliferation at the G2/M phase via the Chk1/cdc25c/cdc2-cyclinB1 pathway. Thus, RAB20 could be a promising prognostic biomarker of advanced PSCC with poor patient survival outcomes and could be a potential therapeutic target.

Background: Lymph node metastasis is the most unfavorable prognostic factor of penile squamous cell carcinoma (PSCC). However, patients with the same lymph node status have different outcomes, and molecular classifiers for precise prognostic assessments are lacking.

Background: Radical inguinal lymph node dissection (rILND) is the most available treatment to cure penile cancer (PC) with limited inguinal-confined disease. However, guidelines regarding acceptable boundaries of rILND are controversial, and consensus is lacking. The authors aimed to standardize the surgical boundaries of rILND with definite pathological evidence and explore the distribution pattern of inguinal lymph nodes (ILNs) in PC. Methods: A total of 414 PC patients from two centers who underwent rILND were enrolled. The ILN distribution was divided into seven zones anatomically for pathological examination. Student’s t test and Kaplan–Meier survival analysis were used. Results: ILNs displayed a funnel-shaped distribution with high density in superior regions. ILNs and metastatic nodes are present anywhere within the radical boundaries. Positive ILNs were mainly concentrated in zone I (51.7%) and zone II (41.3%), but there were 8.7% and 12.3% in inferior zones V and VI, respectively, and 7.1% in the deep ILNs. More importantly, a single positive ILN and first-station positive zone was detected in all seven regions. Single positive ILNs were located in zones I through VI in 40.4%, 23.6%, 6.7%, 18.0%, 4.5%, and 1.1%, respectively, and 5.6% presented deep ILN metastasis directly. Conclusions: The authors established a detailed ILN distribution map and displayed lymphatic drainage patterns with definite pathological evidence using a large cohort of PC patients. Single positive ILNs and first-station metastatic zones were observed in any region, even directly with deep ILN metastasis. Only rILND can ensure tumor-free resection without the omission of positive nodes.