diff --git a/src/anyio/_backends/_asyncio.py b/src/anyio/_backends/_asyncio.py
index 63945b33..11120fa1 100644
--- a/src/anyio/_backends/_asyncio.py
+++ b/src/anyio/_backends/_asyncio.py
@@ -2097,12 +2097,18 @@ async def run_sync_in_worker_thread(
 
                 context = copy_context()
                 context.run(sniffio.current_async_library_cvar.set, None)
-                worker.queue.put_nowait((context, func, args, future, scope))
+                if abandon_on_cancel or scope._parent_scope is None:
+                    worker_scope = scope
+                else:
+                    worker_scope = scope._parent_scope
+
+                worker.queue.put_nowait((context, func, args, future, worker_scope))
                 return await future
 
     @classmethod
     def check_cancelled(cls) -> None:
-        if threadlocals.current_cancel_scope._parent_cancelled():
+        scope = threadlocals.current_cancel_scope
+        if scope.cancel_called or scope._parent_cancelled():
             raise CancelledError
 
     @classmethod
@@ -2112,13 +2118,27 @@ def run_async_from_thread(
         args: tuple[Any, ...],
         token: object,
     ) -> T_Retval:
+        async def task_wrapper(scope: CancelScope) -> T_Retval:
+            __tracebackhide__ = True
+            task = cast(asyncio.Task, current_task())
+            _task_states[task] = TaskState(None, scope)
+            scope._tasks.add(task)
+            try:
+                return await func(*args)
+            finally:
+                scope._tasks.discard(task)
+
         loop = cast(AbstractEventLoop, token)
         context = copy_context()
         context.run(sniffio.current_async_library_cvar.set, "asyncio")
+        wrapper = task_wrapper(threadlocals.current_cancel_scope)
         f: concurrent.futures.Future[T_Retval] = context.run(
-            asyncio.run_coroutine_threadsafe, func(*args), loop
+            asyncio.run_coroutine_threadsafe, wrapper, loop
         )
-        return f.result()
+        try:
+            return f.result()
+        except concurrent.futures.CancelledError:
+            raise CancelledError from None
 
     @classmethod
     def run_sync_from_thread(
diff --git a/src/anyio/_backends/_trio.py b/src/anyio/_backends/_trio.py
index d7556560..3127140c 100644
--- a/src/anyio/_backends/_trio.py
+++ b/src/anyio/_backends/_trio.py
@@ -36,7 +36,6 @@
 import trio.lowlevel
 from outcome import Error, Outcome, Value
 from trio.lowlevel import (
-    TrioToken,
     current_root_task,
     current_task,
     wait_readable,
@@ -894,13 +893,13 @@ def run_async_from_thread(
         args: tuple[Any, ...],
         token: object,
     ) -> T_Retval:
-        return trio.from_thread.run(func, *args, trio_token=cast(TrioToken, token))
+        return trio.from_thread.run(func, *args)
 
     @classmethod
     def run_sync_from_thread(
         cls, func: Callable[..., T_Retval], args: tuple[Any, ...], token: object
     ) -> T_Retval:
-        return trio.from_thread.run_sync(func, *args, trio_token=cast(TrioToken, token))
+        return trio.from_thread.run_sync(func, *args)
 
     @classmethod
     def create_blocking_portal(cls) -> abc.BlockingPortal:
diff --git a/tests/test_from_thread.py b/tests/test_from_thread.py
index c6b1f0aa..0e580462 100644
--- a/tests/test_from_thread.py
+++ b/tests/test_from_thread.py
@@ -16,8 +16,10 @@
 from _pytest.logging import LogCaptureFixture
 
 from anyio import (
+    CancelScope,
     Event,
     create_task_group,
+    fail_after,
     from_thread,
     get_all_backends,
     get_cancelled_exc_class,
@@ -65,7 +67,8 @@ def thread_worker_sync(func: Callable[..., T_Retval], *args: Any) -> T_Retval:
     return from_thread.run_sync(func, *args)
 
 
-async def test_thread_cancelled() -> None:
+@pytest.mark.parametrize("cancel", [True, False])
+async def test_thread_cancelled(cancel: bool) -> None:
     event = threading.Event()
     thread_finished_future: Future[None] = Future()
 
@@ -81,10 +84,15 @@ def sync_function() -> None:
     async with create_task_group() as tg:
         tg.start_soon(to_thread.run_sync, sync_function)
         await wait_all_tasks_blocked()
-        tg.cancel_scope.cancel()
+        if cancel:
+            tg.cancel_scope.cancel()
+
         event.set()
 
-    with pytest.raises(get_cancelled_exc_class()):
+    if cancel:
+        with pytest.raises(get_cancelled_exc_class()):
+            thread_finished_future.result(3)
+    else:
         thread_finished_future.result(3)
 
 
@@ -111,6 +119,40 @@ def sync_function() -> None:
         thread_finished_future.result(3)
 
 
+async def test_cancelscope_propagation() -> None:
+    async def async_time_bomb() -> None:
+        cancel_scope.cancel()
+        with fail_after(1):
+            await sleep(3)
+
+    with CancelScope() as cancel_scope:
+        await to_thread.run_sync(from_thread.run, async_time_bomb)
+
+    assert cancel_scope.cancelled_caught
+
+
+async def test_cancelscope_propagation_when_abandoned() -> None:
+    host_cancelled_event = Event()
+    completed_event = Event()
+
+    async def async_time_bomb() -> None:
+        cancel_scope.cancel()
+        with fail_after(3):
+            await host_cancelled_event.wait()
+
+        completed_event.set()
+
+    with CancelScope() as cancel_scope:
+        await to_thread.run_sync(
+            from_thread.run, async_time_bomb, abandon_on_cancel=True
+        )
+
+    assert cancel_scope.cancelled_caught
+    host_cancelled_event.set()
+    with fail_after(3):
+        await completed_event.wait()
+
+
 class TestRunAsyncFromThread:
     async def test_run_corofunc_from_thread(self) -> None:
         result = await to_thread.run_sync(thread_worker_async, async_add, 1, 2)