Inclusion Criteria:

          1. Part A: Histological or cytological confirmation of a solid tumor and disease
             progression. Part B: Histological or cytological confirmation of ER positive, HER2
             negative breast cancer and disease progression or any other solid tumor with a PIK3CA
             gene mutation. Part C: Histological or cytological confirmation of ER positive, HER2
             negative postmenopausal breast cancer with locally advanced or metastatic disease that
             is eligible for fulvestrant treatment. Part D: Histological or cytological
             confirmation of ER positive, HER2 negative postmenopausal breast cancer with locally
             advanced or metastatic disease that is eligible for fulvestrant treatment. Patients
             must also present with a tumor related mutation of the PIK3CA gene.

          2. Availability of archival tumour tissue sample. If archival sample is not available, a
             fresh tumour biopsy must be provided.

          3. At least one measurable lesion per RECIST v1.1. However, breast cancer patients with
             only bone disease are also eligible.

          4. ECOG Performance Status 0-1.

          5. Adequate organ function at baseline:

               1. Serum total bilirubin ≤ 1.5 x ULN and AST/SGOT and ALT/SGPT ≤ 2.5 x ULN or ≤ 5 x
                  ULN if liver metastases are present.

               2. Creatinine ≤ 1.5 x ULN, or calculated or measured creatinine clearance ≥ 50
                  mL/min, or 24-hour measured urine creatinine clearance ≥ 50 mL/min.

               3. Platelets ≥ 100 x 10^9, Hb ≥ 90 g/L, ANC ≥ 1.5 x 10^9/L.

               4. aPTT ≤ 1.5 x ULN

               5. Fasting glucose < 140 mg/dL (7.8 mmol/L).

               6. Glycated haemoglobin (HbA1c) < 8%

          6. Female patients and male patients with female partners of child bearing potential must
             be using adequate contraception.

        Exclusion Criteria:

          1. Recent chemotherapy, radiotherapy, hormonal therapy, immunotherapy or investigational
             drugs within 21 days or 5 half-days from enrolment.

          2. Received palliative/focal radiotherapy within 2 weeks of first dose of study
             treatment.

          3. Major surgery ≤ 21 days from beginning of study drug

          4. Any of the following cardiac criteria: CHF > Class II, cardiac ventricular arrhythmia
             requiring therapy, unstable angina or new-onset angina, QTcF interval >470ms, abnormal
             ECHO or MUGA at baseline (LVEF <50%).

          5. Leptomeningeal disease

          6. Part A: Intolerable AEs due to other PI3K inhibitors, dual PI3K and mTOR inhibitors or
             AKT inhibitors. Parts B, C, and D: Prior exposure to any of the following:
             pharmacological inhibitors of AKT, PI3K, or dual PI3K and mTOR kinase activity

          7. Strong inhibitors and potent inducers of CYP3A4

          8. Peripheral neuropathy CTCAE v4.03 Grade ≥ 3

          9. Diarrhoea CTCAE v4.03 Grade ≥ 2

         10. Acute or chronic pancreatitis

         11. Clinically manifest diabetes mellitus, history of gestational diabetes mellitus and/or
             known glucose intolerance.

         12. Patients currently receiving any medication that has the potential to prolong the QT
             interval or induce Torsades de Pointes

         13. Spinal cord compression or brain metastases unless asymptomatic and not requiring
             steroids for at least 4 weeks

         14. Patients in the combination arms - known hypersensitivity to fulvestrant

         15. Therapeutic treatment with Coumadin or any other coumarin-derivative anticoagulant

         16. Impaired GI function or GI disease that may interfere with absorption of AZD8835 or
             patients unable to take oral medication

         17. As judged by the investigator any evidence of severe or uncontrolled systemic disease

         18. Patients treated with hematopoietic colony-stimulating growth factors e.g., G-CSF,
             GM-CSF, M-CSF) ≤ 2 weeks prior to start. Erythropoietin or darbepoetin is allowed if
             it was initiated at least 2 weeks prior to entry