Basically there are 3 types of worker classifications:
1. Regular W-2 employees
2. Statutory employees
3. Independent contractors (or self-employed individuals)
A regular W-2 employee can be either a salaried, hourly or commissioned employee. The employer deducts all applicable federal and state income taxes as well as SS and Medicare taxes from the employee's pay.
Statutory employees are basically treated the same as an independent contractor, with one big exception. They are not liable for paying their own SS and Medicare taxes. For purposes of those two taxes only, they are paid as an employee, and the employer withholds those taxes from their pay. But a statutory employee pays all of his own federal and state income taxes.
Independent contractors have no taxes withheld at all from the income they receive.
Regular employees report all of their income on Form 1040. Any unreimbursed business expenses which they have are claimed by filing Form 2106, and then claiming those expenses as part of your itemized deductions on Schedule A. The deductions in that category are limited to those which exceed 2% of your adjusted gross income.
Both statutory employees and independent contractors are treated as self-employed individuals. They both report their income and business expenses on Schedule C. Their net income after expenses is then what is subject to tax. They are not subject to that 2% limitation on business expenses.
As a regular employee, even though you are paid strictly on commission, since you are not classified as a statutory employee, you cannot report your business expenses on Schedule C. There are no exceptions to this rule. You may, however, still claim a deduction for your unreimbursed business expenses, including a home office, by claiming those expenses on Schedule A.
In the example that you cited above about the physician, if he was working as a W-2 employee (the same as you are) and he also had an office in his home, then he could deduct his home office expenses, but they would be deducted on Schedule A, and not on Schedule C.
The only real difference you have here with your expenses is that you will be reporting them on Schedule A which is subject to the 2% limitation. But that is the only place that a regular W-2 employee is allowed to take a deduction for business expenses.