Inclusion Criteria:
* Participant aged ≥ 18 years
* Histologically confirmed solid tumor.
* Radiologically confirmed locally advanced or metastatic disease.
* Eligible for and willing to receive treatment with panitumumab or cetuximab as standard-of-care.
* ECOG Performance Status ≤ 2.
* Adequate organ function as defined as:
--Hepatic:
* Total Bilirubin ≤ 1.5x institutional upper limit of normal (ULN)
* AST(SGOT)/ALT(SGPT) ≤ 3 × institutional ULN ----Participants with liver metastases will be allowed to enroll with AST and ALT levels ≤ 5 x ULN.
* Negative pregnancy test for participants who have not undergone surgical sterilization or shown evidence of post-menopausal status. The following age-specific requirements apply:
--\< 50 years of age:
* Amenorrheic for ≥ 12 months following cessation of exogenous hormonal treatments; and
* Luteinizing hormone and follicle-stimulating hormone levels in the post-menopausal range for the institution; or
* Underwent surgical sterilization (bilateral oophorectomy or hysterectomy).
--≥ 50 years of age:
* Amenorrheic for 12 months or more following cessation of all exogenous hormonal treatments; or
* Had radiation-induced menopause with last menses \>1 year ago; or
* Had chemotherapy-induced menopause with last menses \>1 year ago; or
* Underwent surgical sterilization (bilateral oophorectomy, bilateral salpingectomy, or hysterectomy).
* Participants of childbearing potential and participants with a sexual partner of childbearing potential must agree to use a highly effective method of contraception as described in Section 5.4.2.
* Must have recovered from adverse effects of any prior oncologic treatment (e.g. prior surgery, radiotherapy, or other antineoplastic therapy). CTCAE adverse events less than or equal to grade 1 are acceptable. CTCAE adverse events grade 2 or greater may be acceptable as determined by an investigator with appropriate documentation.
* Able to provide informed consent and willing to sign an approved consent form that conforms to federal and institutional guidelines.
Exclusion Criteria:
* Treatment with an anti-EGFR agent within 90 days of registration.
* Pre-existing facial rash that per the treating investigator would preclude the ability to assess response to topical tretinoin.
* The diagnosis of another malignancy within ≤ 2 years before study enrollment, except for those considered to be adequately treated with no evidence of disease or symptoms and/or will not require therapy during the study duration (i.e., basal cell or squamous cell skin cancer, carcinoma in situ of the breast, bladder or of the cervix, or low-grade prostate cancer with Gleason Score ≤ 6).
* Any other condition that would, in the Investigator's judgment, contraindicate the participant's participation in the clinical study due to safety concerns or compliance with clinical study procedures.
* Systemic active infection including tuberculosis (clinical evaluation that includes clinical history, physical examination, radiographic findings, and TB testing in line with local practice), hepatitis B (known positive HBV surface antigen (HBsAg) result), or hepatitis C.
--Note: Participants with a past or resolved HBV infection (defined as the presence of hepatitis B core antibody \[anti-HBc\] and absence of HBsAg) are eligible. Participants positive for hepatitis C (HCV) antibody are eligible only if polymerase chain reaction is negative for HCV RNA.
* Medical, psychiatric, cognitive, or other conditions that may compromise the participant's ability to understand the participant information, give informed consent, comply with the study protocol or complete the study.
* Known prior severe hypersensitivity to investigational product or any component in its formulations (CTCAE v5.0 Grade ≥ 3).
* Participants taking prohibited medications as described in Section 6.8.2. A washout period of prohibited medications for a period of at least five half-lives or as clinically indicated should occur before the start of treatment.
