Caller states he took a total of six Covid vaccine injections (5th injection); Caller reports the vaccines helped with his Karposi(s) Sarcoma cancer, specifically it helped with the lesions on his legs; Caller states he took a total of six Covid vaccine injections (5th injection); This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  An 84-year-old male patient received BNT162b2 (BNT162B2), on 18Feb2022 as dose 5 (booster), single (Lot number: FJ6369) at the age of 84 years for covid-19 immunisation. The patient's relevant medical history included: "Kaposi's sarcoma", start date: 1998 (unspecified if ongoing); "Melanoma", start date: 2022 (ongoing); "lesions on my legs" (unspecified if ongoing). There were no concomitant medications. Vaccination history included: BNT162b2 (DOSE 1, SINGLE, Lot Number: EL3302), administration date: 22Jan2021, when the patient was 83-year-old, for Covid-19 immunization; BNT162b2 (DOSE 2, SINGLE, Lot Number: EN6201), administration date: 12Feb2021, when the patient was 83-year-old, for covid-19 immunization; BNT162b2 (DOSE 3 (BOOSTER), SINGLE, Lot Number: FC3180), administration date: 07Aug2021, when the patient was 84-year-old, for covid-19 immunization; BNT162b2 (DOSE 4 (BOOSTER), SINGLE, Lot Number: FC3182), administration date: 11Sep2021, when the patient was 84-year-old, for covid-19 immunization. The following information was reported: OFF LABEL USE (non-serious) with onset Feb2022, outcome "unknown", IMMUNISATION (non-serious) with onset 18Feb2022, outcome "unknown" and all described as "Caller states he took a total of six Covid vaccine injections (5th injection)"; THERAPEUTIC RESPONSE UNEXPECTED (non-serious) with onset 18Feb2022, outcome "unknown", described as "Caller reports the vaccines helped with his Karposi(s) Sarcoma cancer, specifically it helped with the lesions on his legs". Relevant laboratory tests and procedures are available in the appropriate section.  Additional information: Caller reported that he was diagnosed in 1998 with Karposi(s) sarcoma not-ing it was caused by there were HHV8 herpes virus adding that, his was extremely rare. Most have HIV with the cancer confirming that he was not HIV positive.  He stated that, discovered this virus and thought the vaccine may have been beneficial by stimulating the innate immune response. Did not have any feelings at all after any of my six Pfizer vaccine injections (2 vaccines and 2 boosters). His phone call to you was not about your vaccine safety issue which you are dealing with. His call was about positive effect of your vaccine injections on lesions of my classic Kaposi sarcoma cancer which unfortunately have. He asked to forward his information to Pfizer scientists who have knowledge of this rare cancer. He worked 27 years as a chemist in developing potential anticancer drugs, and He do know how important and useful his information might be for your scientists dealing with cancer treatment. Patient other (DOSE 6) Date: 20May2022, Lot number: Pfizer FM0173. The caller was trying to tell that he found the vaccine active against his cancer. He found additional usage of the vaccine, against cancer, it could be used as a cancer, to treat cancer and he did write to, he got to call couple times, Pfizer was always sent his this package with questionnaire about quality of vaccine. He was not dealing with,he had no question about quality okay, He need to speak with somebody, Pfizer scientist because what he found was additional usage of vaccine as a anticancer drug.  Follow-Up (22Jun2022): Follow-up attempts are completed. No further information is expected.  Follow-up (07Jul2022): This is a spontaneous follow-up report from a contactable consumer. This consumer (patient) reported in response to Non-HCP letter. Updated information included: Vaccination facility name captured, Other (DOSE 6) Date: 20May2022, Lot number: Pfizer FM0173.  No follow-up attempts are possible. No further information is expected.  Follow-up (05Aug2022): This is a spontaneous follow-up report received from the contactable consumer. This consumer (patient) reported that: Updated information: reporter information (added new reporter), reaction data (added events of Off label use and booster, onset date, outcome) and additional information updated. Event Inappropriate dose of vaccine administered was deleted.  Follow-up attempts are completed. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202200788801 same patient, different vaccine dose/AE;US-PFIZER INC-PV202200004511 same reporter/patient, different dose number/AE.;US-PFIZER INC-202201041610 Same reporter/Patient, different Dose/Event.;