Dark/Black Nail = Cancer?

[heaters]

So, I just read an article about nails and one of the points discussed is having a black line or streak in one of your nails. I just checked mine and my pinky has a faint line darker than the surrounding nail area. I also checked my nails at my feet and one has a brownish spot at the side. The article said that it might be melanoma. I just want to ask if there are other probably causes to the discoloration of the nails other than cancer. I hope it's just one normal discoloration. TIA!



edit: I just researched some cause

Dark Streaks in the Nail

A brown or black streak running lengthwise along the nail can have various causes, some minor and others serious.

A subungual haematoma is a larger collection of blood beneath the nail, caused by a direct blow or crushing injury. It can be very painful, but usually responds to an ice pack, elevation of the affected hand and anti-inflammatory medications such as ibuprofen. In severe cases, the haematoma may have to be drained by a doctor.
A naevus (birthmark) can appear as a dark line in the nail.
Certain drugs, including the antibiotic minocycline, can cause streaking of the nails as a side-effect.
Nail discoloration is common in people with Addison’s disease, a rare disorder of the adrenal gland.
Lichen planus and fungal or bacterial infections can produce streaks on the nails.
A pigmented line in a nail can be a sign of a malignant melanoma or other skin cancer.


so among the causes, what is the most likely cause of the discoloration? I hope its just fungal infection or a nail mole haha. Again TIA!

[heaters]

These are not mine BTW, i just posted some pics. Mines looks like the one on the last picture(right finger) which is not too dark