A Phase 1/2a, Multi-Center, Open-Label Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Preliminary Evidence of Antitumor Activity of JAB-30355 in Adult Patients With Advanced Solid Tumors Harboring TP53 Y220C Mutation

Inclusion Criteria: * Written informed consent. * Participant must be ≥18 years of age at the time of signing the Informed Consent Form (ICF). * ECOG performance status score of 0 or 1. * Has been treated with at least one line of systemic therapy for that tumor type and stage. * Have documentation of confirmed TP53 Y220C mutation. * At least 1 measurable lesion per RECIST v1.1. * Adequate hematological, renal and hepatic function and appropriate coagulation condition. * Able to swallow and retain orally administered medication. Exclusion Criteria: * Active brain or spinal metastases or primary CNS tumor. * Active infection requiring systemic treatment within 7 days. * Active HBV or HCV. * Any severe and/or uncontrolled medical conditions. * LVEF ≤50% assessed by ECHO or MUGA. * QTcF \> 470 msec.