Inclusion Criteria:

        This study will look at solid tumors (as a basket trial for any solid cancer) with HER2
        positivity based on IHC

          1. Histologically confirmed HER2 positive solid tumors, including but not limited to:
             head and neck squamous cell carcinoma; cancer of the salivary glands; lung cancer;
             breast cancer; bladder cancer; gastric cancer; esophageal cancer; colorectal cancer;
             and pancreatic adenocarcinoma. HER2 positivity is defined as ≥2+ staining by IHC with
             either the FDA-approved CB11 antibody (Leica) or anti HER2/neu (4B5) (VENTANA), which
             refers to greater than weak-to-moderate staining intensity in >10% tumor cells.

          2. The disease must be deemed by the appropriate multi-disciplinary tumor board
             unsuitable for curative surgery, radiotherapy, systemic therapy, including checkpoint
             inhibitors, or any combination of the above modalities.

          3. Disease must have progressed after standard first line therapy, or without available
             effective treatment options. Patients are still eligible if they have failed more than
             one line of therapy.

          4. The patient must have at least one tumor site appropriate for intratumoral injection.

          5. The patient must have radiographically measurable disease as per RECIST 1.1.

          6. The patient must have adequate organ function within 7 days prior to consent for
             treatment as indicated by following measures:

               -  Hematologic: Absolute neutrophil count (ANC) ≥1.0 x 109/l; Hemoglobin ≥9 g/dl;
                  Platelet count ≥ 100 x 109/l; PT or PTT ≤ 1.5 x ULN unless the subject is
                  receiving anticoagulation.

               -  Hepatic function: bilirubin < 2 x ULN, and AST and ALT < 3 x ULN

               -  Renal Function: serum creatinine <2 x the ULN or creatinine clearance >60 mL/min.

               -  Cardiac function: LVEF ≥ 55%.

          7. Prior HER2 targeted therapy is allowed if delivered at least 4 weeks prior to the
             enrollment.

          8. Prior immunotherapy is allowed if it was delivered at least 4 weeks prior to the
             enrollment.

          9. Eastern Cooperative Oncology Group (ECOG) performance status 2 or less.

         10. Females of childbearing potential must have a negative pregnancy test and agree to use
             contraception during on-study protocol therapy.

         11. Male subjects with pregnant partner/female partner of childbearing potential agree to
             use barrier contraceptive during the study to minimize the risk of embryo-fetal
             exposure.

         12. The patient is ≥ 18 years of age, and able to understand and give informed consent to
             study related procedures and treatments.

        Exclusion Criteria:

          1. Patients with any concurrent treatment that would compromise the study including but
             not limited to continuous high dose corticosteroids (more than 10mg/day prednisone or
             equivalent dose), lympho-depleting antibodies or cytotoxic agents, CNS metastasis
             requiring continuous high-dose steroids (more than 10mg/day prednisone or equivalent
             dose) or other active therapeutic intervention. This does not include stable,
             previously-treated brain metastases.

          2. Patients at significant risk of airway compromise or other critical obstruction (e.g.
             bowel, ureter, etc.) in the event of possible post injection tumor inflammation based
             on the investigative team's judgement.

          3. History or evidence of active autoimmune disease requiring continuous systemic
             corticosteroids, immunosuppressants or other disease modifying agents.

          4. Evidence of significant immunosuppressive conditions, such as the following:

               -  Post organ transplant.

               -  Diagnosis of HIV or other immunodeficiency disorders.

          5. Diagnosis of other malignancies within 5 years except for cutaneous basal cell or
             squamous cell carcinoma, well-differentiated thyroid cancer, or localized prostate
             cancer.

          6. Patients with known active infectious disease, such as hepatitis B or C infection.

          7. Patient has had acute myocardial infarction within 6 months prior to enrollment for
             treatment.

          8. Patients with abnormal left ventricular function (LVEF <55%). i .Injectable tumor site
             is considered to incur a significant risk of major hemorrhage (e.g. located in the CNS
             (brain), pulmonary parenchyma, and proximal to critical neurovascular structures).

        j. Pregnant or breastfeeding females. k. Uncontrolled intercurrent illness including but
        not limited to psychiatric illness and or social situations that in the opinion of the
        investigator would compromise compliance of study requirements or put the patient at
        unacceptable risk.