Tumour size and probability of malignancy

[StringJunky]

What  changes internally  in a growth  - like an intestinal adenoma (pre-cancer) for example - that makes it malignant? Or why does increasing size mean it increases the chances of it becoming metastatic? Does the already disfunctioning cells increase in disorder in their DNA with each new replication or new generation?

Edited August 10, 2018 by StringJunky

[pavelcherepan]

10 hours ago, StringJunky said:

What  changes internally  in a growth  - like an intestinal adenoma (pre-cancer) for example - that makes it malignant? Or why does increasing size mean it increases the chances of it becoming metastatic? Does the already disfunctioning cells increase in disorder in their DNA with each new replication or new generation?

As far as I understand it, the increase in size of a benign tumor simply increases chances of further random mutations which will eventually allow one to become malignant. Benign tumor cells usually have developed a mutation which allows them to multiply uncontrollably, but can still be contained by the actions of immune system. At the same time this uncontrolled replication increases the chances of further mutations coming along which will alter some of the genes relating to immune response, such as being able to evade natural killer cells. 

https://en.wikipedia.org/wiki/Natural_killer_cell#NK_cell_evasion_by_tumor_cells

From that point on, you get a malignant tumor.

[StringJunky]

31 minutes ago, pavelcherepan said:

As far as I understand it, the increase in size of a benign tumor simply increases chances of further random mutations which will eventually allow one to become malignant. Benign tumor cells usually have developed a mutation which allows them to multiply uncontrollably, but can still be contained by the actions of immune system. At the same time this uncontrolled replication increases the chances of further mutations coming along which will alter some of the genes relating to immune response, such as being able to evade natural killer cells. 

https://en.wikipedia.org/wiki/Natural_killer_cell#NK_cell_evasion_by_tumor_cells

From that point on, you get a malignant tumor.

Thank you Pavel.

[CharonY]

On 8/10/2018 at 6:38 PM, pavelcherepan said:

As far as I understand it, the increase in size of a benign tumor simply increases chances of further random mutations which will eventually allow one to become malignant. Benign tumor cells usually have developed a mutation which allows them to multiply uncontrollably, but can still be contained by the actions of immune system. At the same time this uncontrolled replication increases the chances of further mutations coming along which will alter some of the genes relating to immune response, such as being able to evade natural killer cells. 

https://en.wikipedia.org/wiki/Natural_killer_cell#NK_cell_evasion_by_tumor_cells

From that point on, you get a malignant tumor.

I don't think it is that straightforward. It is more likely that a larger growth is already associated with conditions that increase cancer risk. For example, studies have shown that in patients with ademoma removal the risk of subsequent cancer is higher for those who had high-risk adenomas. I.e. the presence of the mass itself is not necessarily the main cause or source of subsequent cancer formation.

[StringJunky]

46 minutes ago, CharonY said:

I don't think it is that straightforward. It is more likely that a larger growth is already associated with conditions that increase cancer risk. For example, studies have shown that in patients with ademoma removal the risk of subsequent cancer is higher for those who had high-risk adenomas. I.e. the presence of the mass itself is not necessarily the main cause or source of subsequent cancer formation.

They have inherent extra factors that make them prone besides a random mutation that may occur with increased mass? I appreciate type does matter i.e villous types are more prone.

[CharonY]

It is more that there are conditions that may be associated with larger adenoma growth (e.g. genetic factors). Those prone to increased growth are also seem to be at higher risk for cancer (even if the growth is removed).

[StringJunky]

51 minutes ago, CharonY said:

It is more that there are conditions that may be associated with larger adenoma growth (e.g. genetic factors). Those prone to increased growth are also seem to be at higher risk for cancer (even if the growth is removed).

Right. Thanks.