Impact of Duffy-null Associated Neutropenia on Chemotherapy Dosing

The goal of this clinical trial is to: * In Phase 1 (observational) to develop an algorithm for treatment of Duffy-null positive patients for chemotherapy dosing * In Phase 2 (interventional), use the algorithm created in phase 1 to adjust chemotherapy dosing for Duffy-null patients

Inclusion Criteria: * Participant must self-identify as being of Middle Eastern or African descent. * Participant must be diagnosed with histologically or cytologically confirmed solid organ cancer and be treatment naive. * Melanoma is allowed; sarcoma is not eligible. * Secondary malignancies are allowed. * Participants who have received only surgery alone as treatment are eligible * Participant must be between the ages of 18-80. * Participant or their legally authorized representative (LAR) must be able to understand a written informed consent document and be willing to sign it. Exclusion Criteria: * Participants with active and uncontrolled bacterial, viral, or fungal infection requiring IV antibiotics. • Participants may be eligible for the study if the infection is deemed to be under control per investigator's discretion. * Participants who have ever received cytotoxic chemotherapy. • Those who have already started a chemotherapy regimen with moderate likelihood of developing neutropenia will be considered for enrollment at the principal investigator's discretion. * Participants who are receiving concurrent chemo-radiation treatment. * Participants who are taking any other investigational drugs. * Participants who are pregnant or breastfeeding. * Participants that do not agree to be followed according to the study protocol or have cognitive or physical inability to follow the treatment plan.